ML080380059

Submittal of McGuire, Lake Normal Maintenance Monitoring Program: 2006 Summary.

ML080380059
Person / Time
Site:	McGuire, Mcguire
Issue date:	01/29/2008
From:	Brandi Hamilton Duke Energy Corp
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NC0024392
Download: ML080380059 (145)

Text

11 BRUCE H HAMILTON PDuke Vice President WEnergy McGuire Nuclear Station Duke Energy Corporation MG01 VP /12700 Hagers Ferry Road Huntersville, NC 28078 704-875-5333 704-875-4809 fax bhhamilton@duke-energy.corn January 29, 2008 U. S, Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

McGuire Nuclear Station Docket Nos. 50-369, 50-370 Please find attached a copy of the annual "Lake Norman Maintenance Monitoring Program: 2006 Summary," as required by the National Pollutant Discharge Elimination System (NPDES) permit NC0024392. The report includes detailed results and data comparable to that of previous years. The report was submitted to the North Carolina Department of Environment and Natural Resources on January 28, 2008.

Questions regarding this submittal should be directed to Kay Crane, McGuire Regulatory Compliance at (704) 875-4306.

Bruce H. Hamilton C- /

www. duke-energy.com

U. S. Nuclear Regulatory Commission Document Control Desk January 29, 2008 Page 2 cc: Mr. J. F. Stang, McGuire Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Victor McCree Acting Regional Administrator U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 Mr. Joe Brady Senior NRC Resident Inspector McGuire Nuclear Station

LAKE NORMAN MAINTENANCE MONITORING PROGRAM:

2006

SUMMARY

McGuire Nuclear Station: NPDES No. NC0024392 Principal Investigators:

Michael A. Abney John E. Derwort William J. Foris DUKE ENERGY Corporate EHS Services McGuire Environmental Center 13339 Hagers Ferry Road Huntersville, NC 28078 December 2007

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 foundation of this report. Kim Baker, Dave Coughlan, Bob Doby, Duane Harrell, Bryan Kalb, Glenn Long, and Todd Lynn conducted fisheries collections and sample processing.

Jan Williams, Brandy Stames, Bill Foris and Glenn Long performed water quality field collections. John Williamson assembled the plant operating data. Jan Williams, Brandy Stames, Glenn Long, and John Derwort conducted plankton sampling, sorting, and taxonomic processing.

We would also like to thank the following reviewers for their insightful commentary and suggestions: Ron Lewis, and John Velte. Sherry Reid compiled this report.

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TABLE OF CONTENTS EXECUTIVE

SUMMARY

........................................................................ v LIST OF TABLES................................................................................. xi LIST OF FIGURES .............................................................................. xiii CHAPTER 1- MCGUIRE NUCLEAR STATION............................................ 1-1 INTRODUCTION ............................................................................. 1-1 OPERATIONAL DATA FOR 2006 ......................................................... 1-1 CHAPTER 2- WATER CHEMISTRY ......................................................... 2-1 INTRODUCTION ............................................................................. 2-1 METHODS AND MATERIALS ............................................................. 2-1 RESULTS ANT) DISCUSSION ........................................................ I...... 2-4 Precipitation and Air Temperature ......................................................... 2-4 Temperature and Dissolved Oxygen....................................................... 2-5 Reservoir-wide Temperature and Dissolved Oxygen .................................... 2-8 Striped Bass Habitat......................................................................... 2-9 Turbidity and Specific Conductance ...................................................... 2-10 pH and Alkalinity .......................................................................... 2-11 Major Cations and Anions................................................................. 2-11 Nutrients..................................................................................... 2-11 Metals ....................................................................................... 2-12 FUTURE STUDIES.......................................................................... 2-13

SUMMARY

.................................................................................. 2-13 CHAPTER 3- PHYTOPLANKTON............................................................. 3-1 INTRODUCTION ............................................................................. 3-1 METHODS AND MATERIALS............................................................. 3-1 RESULTS AND DISCUSSION .............................................................. 3-2 Standing Crop................................................................................ 3-2 Chlorophyll a .............................................................................. 3-2 Total Abundance............................................................................. 3-4 Seston ......................................................................................... 3-4 Secchi Depths ................................................................................ 3-5 Community Composition....I................................................................ 3-5 Species Composition and Seasonal Succession ........................................... 3-6 FUTURE STUDIES .....................................................3-7

SUMMARY

.....................................I.............................. I................. 3-7 CHAPTER 4- ZOOPLANKTON................................................................ 4-1 INTRODUCTION ............................................................................. 4-1 METHODS AND MATERIALS............................................................. 4-1 iii

RESULTS AND DISCU SSION ...................................................................................... 4-2 Total Abundance .......................................................................................................... 4-2 Comm unity Composition .............................................................................................. 4-4 Copepoda .................................................................................................................. 4-4 Cladocera .................................................................................................................. 4-5 Rotifera... ............ ..................................... 4-5 FUTURE STUDIES .............................................. 4-6 SUMM ARY .................................................................................................................... 4-6 CH APTER 5- FISH ERIE S ............................................................................................... o.5-1 INTRODU CTION ........................................................................................................... 5-1 M ETHOD S AND M ATERIALS .................................................................................... 5-1 Spring Electrofishing Surveys ....................................................... 5-1 5;I.........................

Fall electrofishing surveys for young-of-year bass ........................ 5-2 Summ er striped bass m ortality surveys ........................................................................ 5-2 Striped bass netting survey .......................................................................................... 5-2 Fall hydroacoustics and purse seine ............................................................................. 5-3 Crappie trap-net study .................................................................................................. 5-3 RESULTS AND DISCU SSION ...................................................................................... 5-3 Spring Electrofishing Surveys ...................................................................................... 5-3 Fall electrofishing surveys for young-of-year bass ..................................................... 5-5 Summ er striped bass m ortality surveys ........................................................................ 5-5 Striped bass netting survey .......................................................................................... 5-5 Fall hydroacoustics and purse seine ............................................................................. 5-5 FUTURE STUD IES ........................................................................................................ 5-6 SUM M ARY ................................................................................................................... 5-6 LITERATURE CITED ................. ...................................................................................... L-1 iv

EXECUTIVE

SUMMARY

In accordance with National Pollutant Discharge Elimination System (NPDES) permit number NC0024392 for McGuire Nuclear Station (MNS), the Lake Norman Maintenance Monitoring Program continued during 2006. Overall, no obvious long-term impacts of station operations were observed in water quality, phytoplankton, zooplankton, and fish communities. The 2006 station operation data is summarized and continues to demonstrate compliance with thermal limits and cool water requirements.

The average monthly capacity factors for MNS during critical summer months in 2006 were 100.7% (July), 101.3% (August), and 77.7% (September). Average monthly discharge temperatures were below the 99.0 'F (37.2 'C) thermal limit for these critical months. The volume of cool water in Lake Norman was adequate to comply with both the Nuclear Regulatory Commission Technical Specification requirements and the NPDES discharge water temperature limits.

Annual precipitation in the vicinity of MNS in 2006 totaled 105 cm or 10.9 cm less than observed in 2005 (115.9 cm), and 12.6 cm less than the long-term mean for this area (117.6 cm). Air temperatures in 2006 were warmer than both 2005 and the long-term mean during seven months of the year, and differences were most pronounced in January and December when 2006 temperatures averaged 3.1 'C and 3.4 'C warmer, respectively, than recorded in 2005.

Temporal and spatial trends in water temperature and dissolved oxygen (DO) in 2006 were similar to those observed historically, and all data were within the range of previously measured values. Winter and spring water temperatures in 2006 were generally warmer than observed in 2005 in both the mixing and background zones, and paralleled interannual differences exhibited in air temperatures but with about a one month lag time. Summer water temperatures in 2006 were generally similar to those observed in, 2005, with several exceptions. Water temperatures in the upper 10 m of the water column in June 2006 were as much as 3.8 'C warmer in the mixing zone, and up to 2.7°C warmer in the background zone, than measured in 2005. These differences appear to be related primarily to the antecedent April and May air temperatures which were warmer than both 2005 and the long-term mean.

Similarly, September 2006 metalimnion and hypolimnion temperatures were as great as 4.6 o C warmer than measured in 2005. Fall and early winter water temperatures were generally similar to those measured in 2005, and followed the trend exhibited in air temperatures.

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Some differences were observed between years, especially in November when 2006 temperatures were as much as 4.0 'C cooler than measured in 2005, but overall cooling of the water column proceeded at a similar rate in 2005 and 2006. Temperatures at the discharge location in 2006 were generally similar to 2005 and historically. Discharge temperatures in 2006 were slightly warmer (by a maximum of 2.8 'C) in the summer than observed in 2005.

The warmest discharge temperature of 2006,occurred in August and measured 37.8 °C, or 0.7

'C wanner than measured in August 2005.

Seasonal and spatial patterns of DO in 2006 were reflective of the patterns exhibited for temperature, i.e., generally similar in both the mixing and background zones. Winter and spring DO concentrations in 2006 were generally equal to or slightly lower, in both the background and mixing zones, than measured in 2005 and appeared to be related predominantly to the warmer water column temperatures in 2006 versus 2005. Summer DO values in 2006 were highly variable throughout the water column in both the mixing and background zones ranging from highs of 6 to 8 mg/L in surface waters to lows of 0 to 2 mg/L in bottom waters. All dissolved oxygen values recorded in 2006 during the summer were within the historical range. Considerable differences were observed between 2006 and 2005 late summer and fall DO concentrations in both the mixing and background zone, especially in the metalimnion and hypolimnion during the months of September and November, and to a lesser extent in October. The 2006 late summer and autumn DO data indicated that fall convective reaeration proceeded faster and was more complete throughout the water column than observed in the corresponding months in 2005. Consequently, 2006 water column DO levels in these months were higher than observed in 2005. These between-year differences in DO corresponded strongly with the degree of thermal stratification and interannual differences in air temperatures. The seasonal pattern of DO in 2006 at the discharge location was similar to that measured historically, with the highest values observed during the winter and lowest observed in the summer and early fall. The minimum DO concentration measured at the discharge location in 2006 (5.5 mg/L) occurred in August, and was slightly higher than measured in August, 2005 (4.7 mg/L), but was also 1.4 mg/L higher than the historical minimum.

Reservoir-wide isotherm and isopleth information for 2006, coupled with heat content and hypolimnetic oxygen data, illustrate that Lake Norman thermal and oxygen dynamics are characteristic of historical conditions and similar to other Southeastern reservoirs of comparable size, depth, flow conditions, and trophic status. Physicochemical habitat conditions for adult striped bass habitat in 2006 were more severe than both 2005 and 2004, vi

but similar to conditions observed in 2002 and 2003. Observed striped bass mortalities in 2006 totaled only six fish.

All chemical parameters measured in 2006 were similar to 2005, and within the concentration ranges previously reported for the lake during both preoperational and operational years of MNS. Metal concentrations in 2006 were low or below the analytical reporting limits.

Cadmium, lead, zinc, and copper values did not exceed the State water quality action levels during 2006. Manganese and iron concentrations in the surface and bottom waters were generally low in 2006, except during summer and fall when bottom waters became anoxic releasing forms of these metals into the water column. Iron concentrations did not exceed the State action level of 1.0 mg/L. Manganese levels, however, exceeded the State action level (200 ptg/L) in the bottom waters throughout the lake in the summer and fall. Manganese concentrations measured in 2006 are characteristic of historical conditions.

Lake Norman is classified as oligo-mesotrophic based on long-term, annual mean phytoplankton concentrations. Chlorophyll concentrations during 2006 were most often within historical ranges, however, several record low chlorophyll concentrations were recorded in February, while a few record high concentrations were recorded in November.

Lake-wide mean chlorophyll increased from February through May and August to the annual maximum in November. Maximum chlorophyll concentrations were most often observed up-lake at Locations 15.9 and 69.0, while minimum chlorophyll concentrations were most often recorded from down-lake at Location 2.0. The highest chlorophyll value recorded in 2006, 15.05 gxg/L, was well below the NC State Water Quality standard of 40 gig/L.

Phytoplankton densities and biovolumes during 2006 were generally lower than in 2005.

Phytoplankton densities during 2006 never exceeded the NC guidelines for algae blooms; however, biovolumes at most locations in November were in excess of the state guideline.

Standing crop values in excess of bloom guidelines have been recorded during six previous years of the program. As in past years, higher standing crops were usually observed at up-lake locations, while comparatively low values were noted down-lake.

Seston dry and ash-free weights were more often higher in 2006 than in 2005 and down-lake to up-lake differences were apparent during most quarters. Maximum dry and ash-free weights occurred most often at uplake Location 69.0 while minimum values were always noted downlake at Locations 2.0 through 8.0. The lower proportion of ash-free dry weights vii

to dry weights in 2006 compared to 2005 indicates a decrease in organic composition in 2006 samples.

Secchi depths reflected suspended solids, with shallow depths related to high dry weights.

The lake-wide mean secchi depth in 2006 was slightly higher than in 2005 and was within historical ranges recorded since 1992.

The taxonomic compositiorn of phytoplankton communities during 2006 was similar to those of many previous years. Additionally, 2006 had the highest number of individual taxa yet recorded. Cryptophytes were dominant in February, while diatoms were dominant during May and November. Green algae dominated phytoplankton assemblages during August.

Blue-green algae were less abundant during 2006 than during 2005 and their contribution to total densities seldom exceeded 4%.

The most abundant alga, on an annual basis, was the cryptophyte Rhodomonas minuta. The most abundant diatom in May was Cyclotella stelligera, while the most abundant diatom during November was Tabellaria fenestrata. The small desmid, Cosmarium asphearosporumvar. strigosum was dominant in August 2006. All of these taxa have been common and abundant throughout the Lake Norman Maintenance Monitoring Program.

Maximum zooplankton densities most often occurred in the fall of 2006. Minimum zooplankton densities were noted in the winter and spring. As in past years, epilimnetic densities were higher than whole-column densities. Mean zooplankton densities were generally higher at Background locations than at Mixing Zone locations during 2006. Both seasonal and spatial trends of zooplankton populations were similar to those of the phytoplankton. From around 1997 through 2005, a year-to-year trend, of increasing zooplankton densities was observed among Mixing Zone locations in the spring. However, during the spring of 2006, densities at these locations declined sharply. Long-term trends showed much higher year-to-year variability at Background locations than at Mixing Zone locations.

Epilimnetic zooplankton densities were generally within ranges of those observed in previous years. The exceptions were record high densities during the fall at all locations except Location 15.9.

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One hundred and twenty-one zooplankton taxa have been recorded from Lake Norman since the Program began in 1987 (44 were identified during 2006). One previously unreported taxon, a rotifer, Monommata, was identified during 2006.

Overall relative abundance of copepods increased from 2005 to 2006. Copepods dominated only eight samples most of which were collected during summer. Cladocerans were dominant in five samples during the winter while rotifers were dominant in nearly 68% of all samples. The relative abundance of microcrustaceans decreased slightly in the epilimnion of the Mixing Zone and at Background locations since 2005, but had increased among whole-column samples in the epilimnion since the previous year. Historically, copepods and rotifers have most often shown annual peaks in the spring, while cladocerans continued to demonstrate year-to-year variability.

Copepods were dominated by immature forms with adults rarely accounting for more than 7% of zooplankton densities. The most important adult copepod was Tropocyclops, as was the case in previous years. Bosmina was the predominant cladoceran, as has also been the case in most previous years of the Program. Bosminopsis dominated several cladoceran populations during the summer. The most abundant rotifers observed in 2006, as in many previous years, were Polyarthra,Conochilus,Keratella, and Syncheata.

In accordance with the Lake Norman Maintenance Monitoring Program, monitoring of specific fish population parameters continued during 2006. Spring electrofishing indicated that numbers and biomass of fish in 2006 were generally similar to those noted since 1993.

Additionally, electrofishing indicated that 13 to 17 species of fish and two hybrid complexes comprised fish populations in the three sampling areas. Largemouth bass numbers and biomass continue to decline in recent years and the 2006 numbers and biomass were the lowest recorded since sampling began in 1993. Striped bass mortalities (six) and winter mean relative weights (80) were similar to those observed historically. Hydroacoustic sampling estimated a forage fish population of approximately 62 million in 2006, comparable to previous years. Although purse seine sampling indicated a slight increase in the percentage of alewives in 2006, the percent composition was much lower than in years immediately following their 1999 introduction. During 2006, threadfin shad lengths returned to pre-alewife introduction sizes. Little change was observed in crappie populations in Lake Norman.

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Lake Norman Maintenance Monitoring results from 2006 are consistent with results from previous years. Other than somewhat lower productivity from MNS induced mixing at Locations 2.0 and 5.0, no obvious short-term or long-term impacts were observed in water quality or biota of Lake Norman.

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LIST OF TABLES Table Title Page 1-1 Average monthly capacity factors (%) and monthly average discharge water temperatures for McGuire Nuclear Station during 2006 .................... 1-2 2-1 Water chemistry program for the McGuire Nuclear Station NPDES Maintenance Monitoring Program on Lake Norman ..................... 2-17 2-2 Analytical methods and reporting limits employed in the McGuire Nuclear Station NPDES Maintenance Monitoring Program for Lake Norman ..................... 2-18 2-3 Heat content calculations for the thermal regime in Lake Norman for 2005 an d 20 06 .................................................................................................................... 2 -19 2-4 A comparison of areal hypolimnetic oxygen deficits (AHOD), summer chlorophyll a (Chl a), Secchi depth, and mean depth of Lake Norman and 18 TV A reservoirs ................................................................................. ................. 2-20 2-5 Quarterly surface (0.3 m) and bottom (bottom minus 1 m) water chemistry for the McGuire Nuclear Station discharge, mixing zone, and background locations on Lake Norman during 2005 and 2006 .................................................... 2-21 3-1 Mean chlorophyll a concentrations (jig/L) in composite samples and Secchi depths (in) observed in Lake Norman in 2006 .......................................................... 3-10 3-2 Mean phytoplankton densities (units/mL) and biovolumes (mm3/m3 ) by location and sample month from samples collected in Lake Norman, NC, durin g 200 6 ............................................................. ................................................. 3 -11 3-3 Total mean seston dry and ash free dry weights (in mg/L) from samples collected in Lake N orm an during 2006 .................................................................... 3-11 3-4 Phytoplankton taxa identified in quarterly samples collected in Lake Norman each year from 1991 to 2006 ............................... 3-12 3-5 Dominant classes, their most abundant species, and their percent composition (in parenthesis) at Lake Norman locations during each sam pling period of 2006 .................................... ....................................................... 3-23 4-1 Total zooplankton densities (no. X 1000/m 3 ), densities of major zooplankton taxonomic groups, and percent composition (in parentheses) of major taxa in the epilimnion and whole column net tow samples collected from Lake Norman in February, May, August, and October 2006 ............................................... 4-8 4-2 Zooplankton taxa identified from samples collected quarterly on Lake Norm an from 1987 - 2006 ........................................................................................ 4-10 4-3 Dominant copepod (adults), cladoceran, and rotifer taxa, and their percent composition (in parentheses) of the copepod, cladoceran and rotifer densities by location and sample period in Lake Norman in 2006 ........................... 4-13 5-1 Common and scientific names of fish collected in Lake Norman, 2006 .................... 5-8 xi

LIST OF TABLES, Continued Table Title Page 5-2 Numbers and biomass of fish collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late M arch to early A pril 2006 ................................................................. * ............ 5-9 5-3 Mean total lengths (mm) at age for spotted bass (SPB) and largemouth bass (LMB) collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late March to early April 2006 ................. 5-9 5-4 Mean total length (mm) at age for largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late March to early April 2006 .................................................. 5-10 5-5 Dead striped bass observed in Lake Norman during weekly surveys in July and A ugust 2006 ....................................................................................................... 5-10 5-6 Lake Norman forage fish densities (Number/hectare) and population estimates from hydroacoustic surveys in September 2006 ......................................... 5-11 5-7 Total numbers (N) and percent composition of forage fish, and modal length class of threadfin shad collected in purse seine samples from Lake Norman during late summ er/fall, 1993 - 2006 ................................................................... 5-11 xii

LIST OF FIGURES Figure Title Page 2-1 Water quality sampling locations (numbered) for Lake Norman.

Approximate locations of Marshall Steam Station, and McGuire Nuclear Station are also show n ............................................................................................... 2-24 2-2a Annual precipitation totals in the vicinity of McGuire Nuclear Station ................... 2-25 2-2b Monthly precipitation totals in the vicinity of McGuire Nuclear Station in 2005 and 2006 ........................................................................................................... 2-25 2-2c Mean monthly air temperatures recorded at McGuire Nuclear Station beginning in 1989 ...................................................................................................... 2-26 2-3 Monthly mean temperature profiles for the McGuire Nuclear Station background zone in 2005 and 2006 ......................................................................... 2-27 2-4 Monthly mean temperature profiles for the McGuire Nuclear Station mixing zone in 2005 and 2006 ............................................................................................. 2-29 2-5 Monthly surface (0.3 m) temperature and dissolved oxygen data at the discharge location (loc. 4.0) in 2005 and 2006 ......................................................... 2-31 2-6 Monthly mean dissolved oxygen profiles for the McGuire Nuclear Station background zone in 2005 and 2006 .......................................................................... 2-32 2-7 Monthly mean dissolved oxygen profiles for the McGuire Nuclear Station m ixing zone in 2005 and 2006 .................................................................................. 2-34 2-8 Monthly reservoir-wide temperature isotherms for Lake Norman in 2006 ............... 2-36 2-9 Monthly reservoir-wide dissolved oxygen isopleths for Lake Norman in 2 0 0 6 ........................................................................................................................... 2 -39 2-1 Oa Heat content of the entire water column and the hypolimnion in Lake Norm an in 2006 ........................................................................................................ 2-42 2-10b Dissolved oxygen content and percent saturation of the entire water column and the hypolimnion of Lake Norman in 2006 ......................................................... 2-42 2-11 Striped bass habitat (shaded areas; temperatures < 26 'C and dissolved oxygen ? 2 mg/L) in Lake Norman in June, July, August, September, and October 2006 ................................................................ 2-43 2-12 Lake Norman lake levels, expressed in meters above mean sea level (mmsl) for 2002, 2003, 2004, 2005, and 2006. Lake level data correspond to the water quality sampling dates over this time period ...................... 2-45 3-1 Phytoplankton chlorophyll a, densities, biovolumes, and seston weights at locations in Lake Norman, NC in February, May, August, and November 2 0 0 6 ............................................ .............................................................................. 3-2 4 3-2 Lake Norman phytoplankton chlorophyll a seasonal means for each year since A ugust 1987 ..................................................................................................... 3-25 3-3 Phytoplankton mean chlorophyll a concentrations by location for samples collected in Lake Norman, NC, from February and May 1988 -2006 ..................... 3-26 3-4 Phytoplankton mean chlorophyll a concentrations by location for samples collected in Lake Norman, NC, from August and November 1987 - 2006 .............. 3-27 xiii

LIST OF FIGURES, Continued Figure Title Page 3-5 Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 2.0 in Lake Norman, NC, during 2006 ............................................................................................................... 3-28 3-6 Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 5.0 in Lake Norman, NC durin g 2006 ............................................................................................................... 3-29 3-7 Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 9.5 in Lake Norman, NC durin g 200 6 ............................................................................................................... 3-30 3-8 Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 11.0 in Lake Norman, NC during 200 6 ............................................................................................................... 3-3 1 3-9 Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 15.9 in Lake Norman, NC during 2006 ............................................................................................................... 3-32 4-1 Total zooplankton density by location for samples collected in Lake Norman in 2 0 0 6 ........................................................................................................................ 4 -15 4-2 Zooplankton community composition by sample period and location for epilimnetic samples collected in Lake Norman in 2006 ........................................... 4-16 4-3 Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman, NC, in the winter periods of 1988 - 2006 ..................... 4-17 4-4 Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the spring periods of 1988 - 2006 .............................. 4-18 4-5 Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the summer periods of 1987 - 2006. .......................... 4-19 4-6 Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the fall periods of 1987 -'2006 ................................... 4-20 4-7 Annual percent composition of major zooplankton taxonomic groups from Mixing Zone Locations (Locations 2.0 and 5.0 combined) during 1988 -

2006 (Note: Does not include Location 5.0 in the fall of 2002 or winter samples from 2005) ............................................ 4-21 4-8 Annual percent composition of major zooplankton taxonomic groups from Background Locations (Locations 9.5, 11.0, and 15.9 combined) during 1988 - 2006 (Note: Does not include winter samples from 2005) ........................... 4-22 4-9 Copepod densities during each season of each year among epilimnetic samples collected in Lake Norman from 1990 - 2006 (Mixing Zone = mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15 .9) . ......................................................................................................................... 4 -2 3 xiv

LIST OF FIGURES, Continued Figure Title Page 4-10 Cladoceran densities during each season of each year among epilimnetic samples collected in Lake Norman from 1990 - 2006 (Mixing Zone = mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15 .9 )..................................................................................................................... . 4 -24 4-11 Rotifer densities during each season of each year among epilimnetic samples collected in Lake Norman from 1990 - 2006 (Mixing Zone =mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15 .9) . ......................................................................................................................... 4 -2 5 5-1 Sampling locations and zones in Lake Norman associated with fishery assessm ents ............................................................................................................... 5-12 5-2 Numbers and biomass of fish collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 1993 -

2006 ............. ......................................... 5-13 5-3 Numbers and biomass of spotted bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 2001 -

2 0 066 ........................................................................................................................... 5-14 5-4 Size distributions of spotted bass and largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in L ake Norm an, 2006 ................................................................................................... 5-15 5-5 Mean relative weights (Wr) for spotted bass and largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, M N S) in Lake Norm an, 2006 .................................................................................... 5-16 5-6 Numbers and biomass of largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 1993 -2006 .......... . ....................................... 5-17 5-7 Total number of young-of-year black bass collected from electrofishing five 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 2005 and 2006 .......................................................................................................... 5-18 5-8 Mean total length and mean relative weight (Wr) for striped bass collected from Lake Norman, December 2006. Numbers of fish associated with mean length are inside bars ................................................................................................. 5-18 5-9 Zonal and lakewide population estimates of pelagic forage fish in Lake N orman, 1997 - 2006 ................................................................................................ 5-19 5-10 Size distributions of threadfin shad (TFS) and alewives (ALE) collected in purse seine surveys of Lake Norm an, 2006 ............................................................... 5-19 xv

CHAPTER 1 MCGUIRE NUCLEAR STATION INTRODUCTION The following annual report was prepared for the McGuire Nuclear Station (MNS) National Pollutant Discharge Elimination System (NPDES) permit (# NC0024392) issued by North Carolina Department of Environment and Natural Resources (NCDENR). This report summarizes environmental monitoring of Lake Norman conducted during 2006.

OPERATIONAL DATA FOR 2006 Station operational data for 2006 are listed in Table 1-1. The monthly average capacity factors for MNS were 101.5, 101.4, and 76.2% during July, August, and September, respectively. These are the months when conservation of cool water is most critical and compliance with discharge temperatures is most challenging. These three months are also when the thermal limit for MNS increases from a monthly average of 95.0 'F (35.0 'C) to 99.0 °F (37.2 °C). The average monthly discharge temperature was 98.1 'F (36.7 'C) for July, 98.7 'F (37.1 'C) for August, and 94.5 'F (34.7 'C) for September 2006. The volume of cool water in Lake Norman was tracked throughout the year to ensure that an adequate volume was available to comply with both the Nuclear Regulatory Commission Technical Specification requirements and the NPDES discharge water temperature limits.

1-1

Table 1-1. Average monthly capacity factors (%) and monthly average discharge water temperatures for McGuire Nuclear Station during 2006.

MONTHLY AVERAGE MONTHLY AVERAGE CAPACITY FACTORS (%) NPDES DISCHARGE TEMPERATURES Month Unit 1 Unit 2 Station OF °C January 105.3 105.7 105.5 69.4 20.8 February 105.2 105.8 105.5 69.6 20.9 March 104.9 105.6 105.2 73.4 23.0 April 104.8 105.2 105.0 78.3 25.7 May 102.5 104.0 103.2 84.6 29.2 June 102.3 103.2 102.8 92.6 33.7 July 101.1 101.9 101.5 98.1 36.7 August 101.4 101.4 101.4 98.7 37.1 September 101.5 51.0 76.2 94.5 34.7 October 103.3 0.0 51.6 82.3 27.9 November 104.3 61.4 82.9 74.8 23.8 December 104.9 105.6 105.3 74.0 23.3 Average 103.4 87.6 95.5 82.5 1 28.1 1-2

CHAPTER 2 WATER CHEMISTRY INTRODUCTION The objectives of the water chemistry portion of the MNS NPDES Maintenance Monitoring Program are to:

1. maintain continuity in the chemical data base of Lake Norman to allow detection of any significant station-induced and/or natural change in the physicochemical structure of the lake; and

2. compare, where applicable, these physicochemical data to similar data in other hydropower reservoirs and cooling impoundments in the Southeast.

This report focuses primarily on 2005 and 2006. Where appropriate, reference to pre-2005 data will be made by citing reports previously submitted to the NCDENR.

METHODS AND MATERIALS The complete water chemistry monitoring program for 2006, including specific variables, locations, depths, and frequencies is outlined in Table 2-1. Sampling locations are identified in Figure 2-1. Measurements of temperature, dissolved oxygen (DO), DO saturation, pH, and specific conductance were taken, in situ, at each location with a Hydrolab Data-Sonde (Hydrolab 1986) starting at the lake surface (0.3 m) and continuing at one-meter intervals to lake bottom. Pre- and post-calibration procedures associated with operation of the Hydrolab were strictly followed, and documented in hard-copy format. Hydrolab data were captured and stored electronically, and following a data validation step, converted to spreadsheet format for permanent archival.

Water samples for laboratory analysis were collected with a Kemmerer or Van Dorn water bottle at the surface (0.3 m), and from one meter above bottom, where specified (Table 2-1).

Samples not requiring filtration were placed directly in single-use polyethylene terephthalate 2-1

(PET) bottles which were pre-rinsed in the field with lake water just prior to obtaining a sample. Samples for the analysis of total metals were placed directly in pre-acidified PET bottles. Samples requiring filtration were processed in the field by filtering through a 0.45 ptm filter (Gelman AquaPrep 600 Series Capsule) which was pre-rinsed with 500 mL of sample water. Upon collection, all water samples were immediately preserved and stored in the dark, and on ice, to minimize the possibility of physical, chemical, or microbial transformation.

Analytical methods, reporting limits and sample preservation techniques employed were identical to those used in 2005, and are summarized in Table 2-2. All laboratory water quality analyses were performed by the Duke Energy analytical laboratory located in Huntersville, NC. This laboratory is certified to perform analytical assessments for inorganic and organic parameters in North Carolina (North Carolina DWQ Laboratory Certification program, certificate number 248), South Carolina (South Carolina Department of Health and Environmental Control, certificate number 99005), and New York (New York Department of Health, certificate number 11717).

A comprehensive Quality Assurance/Quality Control Program (QA/QCP) is fundamental to the collection, reporting, and interpretation of water quality data, and most investigators implement some type of QA/QCP to identify, quantify, and document bias and variability in data resulting from the collection, processing, shipping, handling and analysis of samples by field and laboratory personnel. Both the United States Environmental Protection Agency (USEPA 1998a, b) and the United States Geological Survey (USGS 1998, 2002) require that any agency-funded project have an approved quality assurance program, and that this program incorporate both a field and laboratory component. USGS also requires that any agency funded study that includes laboratory assessments must also participate in their Standard Reference Program (SRP). This program was originally developed by USGS in the 1960's and currently involves analysis by participating laboratories of standards (blind unknowns) created by the agency on a biannual schedule (USGS 2002).

The QA/QCP employed for this study followed the recommendation of the USEPA and USGS, and included both a field and laboratory component. Field blanks, i.e. Milli-Q water placed in sample bottles, were subjected to the same sample collection and handling procedures, including filtration, applied to actual samples. Periodically, samples were also split prior to submitting to the laboratory for analysis with the goal of quantifying intra-sample analytical variability. The laboratory QA/QCP involved a variety of techniques commonly used in analytical chemistry and included reagent blanks, spikes, replicates, and 2-2

performance samples. To supplement this program, additional performance samples were run on the major ions and nutrients. Beginning in 2005, standards were purchased from the USGS, through the agency's SRS program, and submitted biannually to Duke's laboratory to serve as a "double blind" assessment of analytical performance. These standards allowed quantification of the uncertainty of the analytical results against known values that were within the same concentration matrix as actual samples. The goal of this effort is to assemble analytical uncertainty data for chemical analytes which can be incorporated into statistical analyses assessing trends in time or space.

Water quality data were subjected to various graphical and statistical techniques in an attempt to describe spatial and temporal trends within the lake, and interrelationships among constituents. Whenever analytical results were reported to be equal to or less than the method reporting limit, these values were set equal to the reporting limit for statistical purposes. Data were analyzed using two approaches, both of which were consistent with earlier Duke Power Company, Duke Power, and Duke Energy studies on the lake (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; and Duke Energy 2006).

The first method involved partitioning the reservoir into mixing, background, and discharge zones, consolidating the data into these sub-sets, and making comparisons among zones and years. In this report, the discharge includes only Location 4; the mixing zone, Locations 1 and 5; the background zone includes Locations 8, 11, and 15 (Figure 2-1). The second approach, applied primarily to the in situ data, emphasized a much broader lake-wide investigation and encompassed the plotting of monthly isotherms and isopleths, and summer striped bass habitat. Several quantitative calculations were also performed on the in situ data; these included the calculation of the areal hypolimnetic oxygen deficit (AHOD), maximum whole-water column and hypolimnion oxygen content, maximum whole-water column and hypolimnion heat content, mean epilimnion and hypolimnion heating rates over the stratified period, and the Birgean heat budget.

Heat content (Kcal/cm 2 ), oxygen content (mg/cm2 ), and mean oxygen concentration (mg/L) of the reservoir were calculated according to Hutchinson (1957), using the following equation:

Zm Lt = Ao-lfz0 TO Az dz where; 2-3

Lt = reservoir heat (Kcal/cm 2) or oxygen (mg/cm 2) content Ao = surface area of reservoir (cm2 )

TO = mean temperature (0 C) or oxygen content (mg/L) of layer z Az = area (cm 2) at depth z dz = depth interval (cm)

Zo= surface Zm = maximum depth (m)

Precipitation and air temperature data were obtained from a meteorological monitoring site established near MNS in 1975. These data are employed principally by Duke Energy as input variables into meteorological modeling studies to address safety issues associated with potential radiological releases into the atmosphere by MNS (Duke Power 2004b), as required by the Nuclear Regulatory Commission. The data also serve to document localized temporal trends in air temperatures and rainfall patterns. Data on lake level and hydroelectric flows were obtained from Duke Energy-Carolinas Fossil/Hydro Generation, which monitors these metrics hourly.

RESULTS AND DISCUSSION Precipitation and Air Temperature Annual precipitation in the vicinity of MNS in 2006 totaled 105 cm (Figures 2-2a, b) or 10.9 cm less than observed in 2005 (115.9 cm), and 12.6 cm less than the long-term precipitation average for this area (117.6 cm), based on Charlotte, NC airport data. Monthly rainfall in 2006 was greatest in August with 16.7 cm. This value represented the 4 th wettest August in the last 32 years, and was over double the long-term monthly mean for August (8.3 cm).

Duke Energy reported that air temperatures near the McGuire Nuclear Station in 2005 were generally warmer than the long-term mean, based on monthly average data (Duke Energy 2006). Monthly mean air temperatures in 2006 near the nuclear facility were warmer than both 2005 and the long-term mean for the months of January, March, April, June, July, November, and December (Figure 2-2c). The temporal differences were most pronounced in January and December when 2006 temperatures averaged 3.1 and 3.4 °C warmer, respectively, than recorded in 2005.

2-4

Temnerature and Dissolved Oxvwen Water temperatures measured in 2006 illustrated similar temporal and spatial trends in the background and mixing zones (Figures 2-3 and 2-4), as they did in 2005. This similarity in temperature patterns between zones has been a dominant feature of the thermal regime in Lake Norman since MNS began operations in 1983. When between-zone differences in temperatures are observed, they occur predominately during the cooling period, and can be traced to the influence of the thermal discharge at MNS.

Winter and spring water temperatures in 2006 were generally warmer than those observed in 2005 in both the mixing and background zones, and paralleled interannual differences exhibited in air temperatures, but with about a one-month lag time (Figures 2-2c, 2-3, and 2-4). Because lake sampling is generally performed in the first week of each month, the observed data reflects the cumulative influences of meteorology and hydrology during the previous month. Similarly, January 2006 epilimnion temperatures were cooler than observed in 2005, particularly in the background zone, and undoubtedly were related to the December 2005 air temperatures which were also cooler than the long-term mean. Minimum water temperatures in 2006 were recorded in early February and ranged from 7.1 'C to 9.6 'C in the background zone and from 7.8 'C to 16.1 'C in the mixing zone. Minimum water temperatures measured in 2006 were within the observed historical range (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Summer water temperatures in 2006 were generally similar to those observed in 2005, with several exceptions. The greatest between-year variability in summer water temperature was observed in June in both the mixing and background zorfes, with the primary differences occurring in the upper 10 m of the water column (Figures 2-3 and 2-4). Water temperatures in 2006 in this portion of the water column were up to 3.8 'C warmer in the mixing zone, and up to 2.7°C warmer in the background zone than measured in 2005. These differences appear to be related primarily to the antecedent April and May air temperatures (Figure 2-2c).

Similarly, September 2006 metalimnion and hypolimnion temperatures were as much as 4.6

'C warmer than measured in 2005 (Figures 2-3 and 2-4).

Fall and early winter water temperatures (October, November, and December) in 2006 were generally similar to those measured in 2005, and followed the trend exhibited in air 2-5

temperatures (Figures 2-2c, 2-3). Some differences were observed between years, especially in November when 2006 temperatures were as much as 4.0 'C cooler than measured in 2005, but overall cooling of the water column proceeded at a similar rate in 2005 and 2006.

Temperatures at the discharge location in 2006 were generally similar to 2005 (Figure 2-5) and historically ((Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). Temperatures in 2006 were slightly warmer (by a maximum of 2.8 0C) in the summer than observed in 2005. The warmest discharge temperature of 2006 at Location 4 occurred in August and measured 37.8 'C, or 0.7 'C warmer than measured in August, 2005 (Duke Energy 2006).

Seasonal and spatial patterns of DO in 2006 were reflective of the patterns exhibited for temperature, i.e.; generally similar in both the mixing and background zones (Figures 2-6 and 2-7). As observed with water column temperatures, this similarity in DO patterns between zones has been a dominant feature of the oxygen regime in Lake Norman since MNS began operations in 1983.

Winter and spring DO values in 2006 were generally equal to or slightly lower, in both the background and mixing zones, than measured in 2005 (Figures 2-6 and 2-7). The interannual differences in DO values measured during this period appear to be related predominantly to the warmer water column temperatures in 2006 versus 2005. Warmer water would be expected to exhibit a lesser oxygen content because of the direct effect of temperature on oxygen solubility, which is an inverse relationship, and indirectly via a restricted convective mixing regime which would limit water column reaeration. The greatest differences in DO between 2006 and 2005 during this period were observed in May. In the mixing zone, May 2006 DO concentrations ranged from about 0.5 to 1.6 mg/L less throughout the water column than in 2005. A similar trend was observed in the background zone where DO concentrations ranged from about 0.5 to 2.3 mg/L less throughout the water column than measured in 2005.

Summer DO values in 2006 were highly variable throughout the water column in both the mixing and background zones ranging from highs of 6 to 8 mg/L in surface waters to lows of 0 to 2 mg/L in bottom waters. This pattern is similar to that measured in 2005 and earlier years (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2-6

2006). All dissolved oxygen values recorded in 2006 during this period were within the historical range.

Considerable differences were observed between 2006 and 2005 late summer and fall DO values in both the mixing and background zone, especially in the metalimnion and hypolimnion during the months of September and November, and to a lesser extent in October (Figures 2-6 and 2-7). These interannual differences in DO levels during the cooling season are common in Catawba River reservoirs and can be explained by the effects of variable weather patterns on water column cooling (heat loss) rates and mixing. Warmer air temperatures delay water column cooling which, in turn, delays the onset of convective mixing of the water column and the resultant reaeration of the metalimnion and hypolimnion.

Conversely, cooler air temperatures increase the rate and magnitude of water column heat loss, thereby promoting convective mixing and resulting in higher DO values earlier in the year.

The 2006 late summer and autumn DO data indicate that fall convective reaeration proceeded faster and was more complete throughout the water column than observed in the corresponding months in 2005. Consequently, 2006 DO levels in either a portion or all of the water column in these months in 2006 were higher than observed in 2005. These between-year differences in DO corresponded strongly with the degree of thermal stratification which, as discussed earlier, correlated with interannual differences in air temperatures (Figures 2-2c, 2-3, and 2-4). Interannual differences in DO patterns are common not only within the Catawba River Basin, but throughout Southeastern reservoirs, and can reflect yearly differences in hydrologic, meteorologic, and limnologic forcing variables (Cole and Hannan 1985; Petts, 1984).

The seasonal pattern of DO in 2006 at the discharge location was similar to that measured historically, with the highest values observed during the winter and lowest observed in the summer and early fall (Figure 2-5). Summer and fall DO levels in 2006 at location 4.0 were slightly higher (range = 0.6 to 1.3 mg/L) than observed 2005. The lowest DO concentration measured at the discharge location in 2006 (5.5 mg/L) occurred in August, and was slightly higher than measured in August, 2005 (4.7 mg/L), but was also 1.4 mg/L higher than the historical minimum, measured in August 2003 (4.1 mg/L).

2-7

Reservoir-wide Temperature and Dissolved Oxygen The monthly reservoir-wide temperature and DO data for 2006 are presented in Figures 2-8 and 2-9. These data are similar to that observed in previous years and are characteristic of cooling impoundments and hydropower reservoirs in the Southeast (Cole and Hannan 1985; Hannan et al. 1979; Petts 1984). Detailed discussions on the seasonal and spatial dynamics of temperature and dissolved oxygen during both the cooling and heating periods in Lake Norman have been presented previously (Duke Power Company 1992, 1993, 1994, 1995, 1996).

The seasonal heat content of both the entire water column and the hypolimnion for Lake Norman in 2006 are presented in Figure 2-10a; additional information on the thermal regime in the reservoir for the years 2005 and 2006 is found in Table 2-3. Annual minimum heat content for the entire water column in 2006 (10.85 Kcal/cm2; 10.48 'C) occurred in early January, whereas the maximum heat content (28.88 Kcal/cm 2 ; 28.31 'C) occurred in early August. Heat content of the hypolimnion exhibited a somewhat different temporal trend as that observed for the entire water column. Annual minimum hypolimnetic heat content also occurred in early January and measured 6.07 Kcal/cm 2 (10.94 0 C), but the maximum occurred in mid August and measured 16.82 Kcal/cm 2 (25.56 'C). Heating of both the entire water column and the hypolimnion occurred at approximately a linear rate from minimum to maximum heat content. The mean heating rate of the entire water column equaled 0.091 C/day and 0.076 'C/day for the hypolimnion; both rates were slightly lower than observed in 2005 (Table 2-3). The 2006 heat content and heating rate data for Lake Norman were generally similar to that observed in previous years (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

The seasonal oxygen content and percent saturation of the whole water column, and the hypolimnion, are depicted for 2006 in Figure 2-10b. Additional oxygen data can be found in Table 2-4 which presents the 2006 AHOD for Lake Norman and similar earlier estimates for 18 Tennessee Valley Authority (TVA) reservoirs. Reservoir oxygen content was greatest in mid-winter when DO content measured 9.8 mg/L for the whole water column and 9.6 mg/L for the hypolimnion. Percent saturation values at this time approached 92% for the entire water column and 87% for the hypolimnion. tieginning in early spring, oxygen content began to decline precipitously in both the whole water column and the hypolimnion, and continued to decline linearly until reaching a minimum in mid summer. Minimum summer 2-8

volume-weighted DO values for the entire water column measured 4.2 mg/L (55%

saturation), whereas the minimum for the hypolimnion was 0.28 mg/L (3.3% saturation).

The mean rate of DO decline in the hypolimnion over the stratified period, i.e., the AHOD, was 0.037 mg/cm2/day (0.059 mg/L/day) (Figure 2-10b), and is similar to that measured in 2005 (Duke Energy 2006).

Hutchinson (1938, 1957) proposed that the decrease of DO in the hypolimnion of a waterbody should be related to the productivity of the trophogenic zone. Mortimer (1941) adopted a similar perspective and proposed the following criteria for AHODs associated with various trophic states; oligotrophic < 0.025 mg/cm 2/day, mesotrophic 0.026 mg/cm 2/day to 0.054 mg/cm 2/day, and eutrophic _ 0.055 mg/cm 2/day. Employing these limits, Lake Norman should be classified as mesotrophic based on the calculated AHOD value of 0.037 mg/cm 2/day for 2006. The oxygen-based mesotrophic classification agrees well with the mesotrophic classification based on chlorophyll a levels (Chapter 3). The 2006 AHOD value is also similar to that found in other Southeastern reservoirs of comparable depth, chlorophyll a status, and Secchi depth (Table 2-4).

Striped Bass Habitat Suitable pelagic habitat for adult striped bass, defined as that layer of water with temperatures

< 26 'C and DO levels _>2.0 mg/L, was found lake-wide from mid September 2005 through early July 2006. Beginning in late June 2006, habitat reduction proceeded rapidly throughout the reservoir both as a result of deepening of the 26 'C isotherm and metalimnetic and hypolimnetic deoxygenation (Figure 2-11). Habitat reduction was most severe from mid July through early September when no suitable habitat was observed in the reservoir. These conditions were similar to those observed in most previous years except that in 2006 no habitat existed in the upper portions of the reservoir. Historically, a small, -but spatially variable zone of habitat is typically observed in the summer in the upper, riverine portion of the reservoir, near and upstream of the confluence of Lyles Creek with Lake Norman.

Habitat measured in the upper reaches of the reservoir appears to be influenced by both inflow from Lyles Creek and discharges from Lookout Shoals Hydroelectric facility, which generally are somewhat cooler than ambient conditions in Lake Norman. Upon entering Lake Norman, this water mixes with ambient waters and then proceeds as a subsurface underflow as it migrates downriver (Ford 1985).

2-9

An additional refuge was also observed in the metalimnion and hypolimnion, near the dam during this period, but this lasted only until 26 July when dissolved oxygen was reduced to <

2.0 mg/L by microbial demands, thereby eliminating suitable habitat in the lower portion of the reservoir. Summer-time habitat conditions for adult striped bass in 2006 were more severe than in both 2005 and 2004, when the largest striped bass die-off ever was observed in the reservoir (2610 fish). Conditions in 2006 were most recently similar to those measured in 2002 and 2003 when habitat elimination was observed for a period of about 30-35 days.

Observed striped bass mortalities in 2006 totaled six fish (Chapter 5).

Physicochemical habitat was observed to have expanded appreciably by mid September, primarily as a result of epilimnion cooling and deepening, and in response to changing meteorological conditions. The temporal and spatial pattern of striped bass habitat expansion and reduction observed in 2006 was generally similar to that previously reported in Lake Norman, and many other Southeastern reservoirs (Coutant 1985; Matthews et al. 1985; Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992; 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Turbidity and Specific Conductance Surface turbidity values were generally low at the MNS discharge, mixing zone, and mid-lake background locations during 2006, ranging from 1.0 to 5.3 NTU's (Table 2-5). The lone exception occurred in August in the lower segment of the lake when surface values ranged from 1.4 to 22 NTU's. Bottom turbidity values were also low over the 2006 study period, except in August when values ranged from 1.7 to 20 NTU's (Table 2-5). Turbidity values observed in 2006, as a whole, were higher than measured in 2005 (Table 2-5), but within the historical. range (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Specific conductance in Lake Norman in 2006 ranged from 55 to 67 umho/cm, and was generally similar to that observed in 2005 (Table 2-5), and historically (Duke Power Company 1985,1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). Specific conductance values in surface and bottom waters in 2006 were similar throughout the year except during the period of intense thermal stratification, i.e., August, when an increase in bottom conductance values was observed in both the mixing and background zones. These 2-10

increases in bottom conductance values appeared to be related primarily to the release of soluble iron and manganese from the lake bottom under anoxic conditions (Table 2-5): This phenomenon is common in both natural lakes and reservoirs that exhibit extensive hypolimnetic oxygen depletion (Hutchinson 1957, Wetzel 1975), and is an annually recurring phenomenon in Lake Norman.

pH and Alkalinity During 2006, pH and alkalinity values were similar among MNS discharge, mixing, and background zones (Table 2-5). Values of pH were also generally similar to values measured in 2006 (Table 2-5), and historically (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). Values of pH in 2006 ranged from 7.0 to 7.9 in surface waters, and from 6.2 to 7.5 in bottom waters. Alkalinity values in 2006 ranged from 11.5 to 15.5 mg/L, expressed as CaCO 3, in surface waters and from 12.0 to 17.5 mg/L in bottom waters.

Major Cations and Anions The concentrations of major ionic species in the MINS discharge, mixing, and mid-lake background- zones are provided in Table 2-5. Lake-wide, the major cations were sodium, calcium, magnesium, and potassium, whereas the major anions were bicarbonate, sulfate, and chloride. The overall ionic composition of Lake Norman during 2006 was generally similar to that reported for 2005 (Table 2-5) and previously ((Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Nutrients Nutrient concentrations in the discharge, mixing, and mid lake background zones of Lake Norman for 2005 and 2006 are provided in Table 2-5. Overall, nutrient concentrations in 2006 were well within historical ranges (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). Nitrogen and phosphorus levels in 2006 were low and generally similar to those measured in 2005 (Duke Power 2005). Total phosphorus and ortho-phosphorus concentrations were typically measured at or below the analytical reporting 2-11

limits (ARL) for these constituents, i.e., 5 jig/L. (Note that the reporting limit for total phosphorus was lowered from 10 pgg/L to 5 jig/L in 2005). For total phosphorus, all 44 samples analyzed in 2006 exceeded the ARL, but most measurements (42 of 44) were 5 10 gig/L, and the maximum recorded value was 15 gig/L. For ortho-phosphorus all 44 of the samples assayed measured < 5 jig/L. Nutrients in 2006 were generally somewhat higher in the upper portions of the reservoir compared to the lower sections, but the differences were slight and not statistically significant (p < 0.05). Spatial variability in various chemical constituents, especially nutrient concentrations, is common in long, deep reservoirs (Soballe et al. 1992). Nitrite-nitrate and ammonia nitrogen concentrations were low at all locations sampled in 2006 (Table 2-5), and also were generally similar to 2005 and historical values (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Metals Metal concentrations in the discharge, mixing, and mid lake background zones of Lake Norman for 2006 were similar to those measured in 2005 (Table 2-5) and historically (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). Iron concentrations in surface and bottom waters were generally low (< 0.4 mg/L) during 2006, the lone exception being a 0.56 mg/L value measured in the bottom waters at Location 5.0 in August. Nowhere in the reservoir in 2006 did iron concentrations exceed the North Carolina water quality action level for iron (1.0 mg/L; NCDENR 2004), which is unusual.

Historically, iron concentrations typically increase in the bottom waters during the late summer, and early fall, in response to changing redox conditions (see below). It's unclear why this phenomenon was not as prevalent in 2006 and 2005, as in previous years.

Similarly, manganese concentrations in the surface and bottom waters were generally low (_

100 gig/L) in 2006, except during the summer and fall when bottom waters were anoxic (Table 2-5). Manganese concentrations were also higher in 2006 than 2005, especially in the bottom waters, and were similar to values measured in 2004. This phenomenon, i.e., the release of manganese (and iron) from bottom sediments in response to low redox conditions (low oxygen levels), is common in stratified waterbodies (Stumm and Morgan 1970, Wetzel 1975). Manganese concentrations in the bottom waters rose above the State water quality action level for this constituent (200 gg/L; NCDENR 2004) at various locations throughout the lake in summer and fall of 2006, and were characteristic of historical conditions (Duke 2-12

Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006).

Concentrations of other metals in 2006 were typically low, and often below the analytical reporting limit for the specific constituent (Table 2-5). These findings are similar to those observed for earlier years (Duke Power Company 1985, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996; Duke Power 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004a, 2005; Duke Energy 2006). All values for cadmium, lead and zinc were reported as either equal to or below the reporting limit for each constituent, and no State NC water quality standard or action level was exceeded. All copper concentrations were less than 3 tg/L, and the maximum concentration reported was 2.8 gtg/L. All copper values reported were below the State action level of 7 gtg/L (NCDENR 2004).

FUTURE STUDIES No changes are planned for the water chemistry portion of the Lake Norman Maintenance-Monitoring Program.

SUMMARY

Annual precipitation in the vicinity of MNS in 2006 totaled 105 cm or 10.9 cm less than observed in 2005 (115.9 cm), and 12.6 cm less than the long-term mean for this area (117.6 cm). August 2006 rainfall totaled 16.7 cm which was the 4th wettest August in the last 32 years, and was over double the long-term monthly mean for August. Air temperatures in 2006 were warmer than both 2005 and the long-term mean for the months of January, March, April, June, July, November, and December. Temporal differences were most pronounced in January and December when 2006 temperatures averaged 3.1 'C and 3.4 'C warmer, respectively, than recorded in 2005.

Temporal and spatial trends in water temperature and DO in 2006 were similar to those observed historically, and all data were within the range of previously measured values.

Winter and spring water temperatures in 2006 were generally warmer than observed in 2005 in both the mixing and background zones, and paralleled interannual differences exhibited in air temperatures but with about a one month lag time. Summer water temperatures in 2006 2-13

were generally similar to that observed in 2005, with several exceptions. The greatest between-year variability in summer water temperature was observed in June in both the mixing and background zones, with the primary differences occurring in the upper 10 m of the water column. Water temperatures in 2006 in this portion of the water column were up to 3.8 'C warmer in the mixing zone, and up to 2.7. C warmer in the background zone than measured in 2005. These differences appear to be related primarily to the antecedent April and May air temperatures. Similarly, September 2006 metalimnion and hypolimnion temperatures were as great as 4.6 'C warmer than measured in 2005.

Fall and early winter water temperatures (October, November, and December) in 2006 were generally similar to those measured in 2005, and followed the trend exhibited in air temperatures. Some differences were observed between years, especially in November when 2006 temperatures were as much as 4.0 'C cooler than measured in 2005, but overall cooling of the water column proceeded at a similar rate in 2005 and 2006.

Temperature data at the discharge location in 2006 were generally similar to 2005 and historically. Temperatures in 2006 were slightly warmer (by a maximum of 2.8 'C) in the summer than observed in 2005. The warmest discharge temperature of 2006 occurred in August and measured 37.8 'C, or 0.7 °C warmer than measured in August 2005.

Seasonal and spatial patterns of DO in 2006 were reflective of the patterns exhibited for temperature, i.e., generally similar in both the mixing and background zones. Winter and spring DO values in 2006 were- generally equal to or slightly lower, in both the background and mixing zones, than measured in 2005. The interannual differences in DO values measured during this period appear to be related predominantly to the warmer water column temperatures in 2006 versus 2005. The greatest differences in DO between 2006 and 2005 during this period were observed in May. In the mixing zone, May 2006 DO concentrations ranged from about 0.5 to 1.6 mg/L less throughout the water column than in 2005. A similar trend was observed in the background zone where DO concentrations ranged from about 0.5 to 2.3 mg/L less throughout the water column than measured in 2005.

Summer DO values in 2006 were highly variable throughout the water column in. both the mixing and background zones ranging from highs of 6 to 8 mg/L in surface waters to lows of 0 to 2 mg/L in bottom waters. All dissolved oxygen values recorded in 2006 during this period were within the historical range Considerable differences were observed between 2006 and 2005 late summer and fall DO values in both the mixing and background zone, 2-14

especially in the metalimnion and hypolimnion during the months of September and November, and to a lesser extent in October. The 2006 late summer and autumn DO data indicated that fall convective reaeration proceeded faster and was more complete throughout the water column than observed in the corresponding months in 2005. Consequently, 2006 DO levels in a portion or all of the water column in these months in 2006 were higher than observed in 2005. These between-year differences in DO corresponded strongly with the degree of thermal stratification and interannual. differences in air temperatures The seasonal pattern of DO in 2006 at the discharge location was similar to that measured historically, with the highest values observed during the winter and lowest observed in the summer and early fall. Summer and fall DO levels in 2006 at location 4.0 were slightly higher (range = 0.6 to 1.3 mg/L) than observed in 2005. The lowest DO concentration measured at the discharge location in 2006 (5.5 mg/L) occurred in August, and was slightly higher than measured in August, 2005 (4.7 mg/L), but was also 1.4 mg/L higher than the historical minimum, measured in August 2003 (4.1 mg/L).

Reservoir-wide isotherm and isopleth information for 2006, coupled with heat content and hypolimnetic oxygen data, illustrated that Lake Norman exhibited thermal and oxygen dynamics characteristic of historical conditions and similar to other Southeastern reservoirs of comparable size, depth, flow conditions, and trophic status. Summer-time habitat conditions for adult striped bass in 2006 were more severe than in both 2005 and 2004, when the largest striped bass die-off ever was observed in the reservoir (2610 fish). Conditions in 2006 were most recently similar to those measured in 2002 and 2003 when habitat elimination was observed for a period of about 30-35 days. Observed striped bass mortalities in 2006 totaled six fish.

All chemical parameters measured in 2006 were similar to 2005, and within the concentration ranges previously reported for the lake during both preoperational and operational years of MNS. Specific conductance values, and all concentrations Of cation and anion species measured, were low. Nutrient concentrations were also low with most values reported close to or below the analytical reporting limit for that test. Concentrations of metals in 2006 were low, and often below the analytical reporting limits. All values for cadmium, lead and zinc were reported as either equal to or below the reporting limit for each constituent, and no State water quality standard or action level was exceeded. All copper concentrations were less than 3 ptg/L, and the maximum concentration reported in 2006 was 2.8 pg/L.

2-15

Iron concentrations in surface and bottom waters were generally low (< 0.4 mg/L) during 2006, the lone exception being a 0.56 mg/L value measured in the bottom waters at Location 5.0 in August. Nowhere in the reservoir in 2006 did iron concentrations exceed State water quality action levels for this constituent (1.0 mg/L). Similarly, manganese concentrations in the surface and bottom waters were generally low (< 100 gtg/L) in 2006, except during the summer and fall when bottom waters were anoxic. Manganese concentrations were also higher in 2006 than 2005, especially in the bottom waters, and were similar to values measured in 2004. Manganese concentrations in the bottom -waters rose above the North Carolina action level for this constituent, i.e., 200 jtg/L, at various locations throughout the lake in summer and fall of 2006, and were characteristic of historical conditions.

2-16

Table 2-1. Water chemistry program for the McGuire Nuclear Station NPDES Maintenance Monitoring Program on Lake Norman.

2006 McGUTIRE NPDES SAMPLING PROGRAM PARAMETERS LOCATIONS 2 4 5 8 9.5 11 13 14 15 15.9 62 69 72 80 16 DEPTH (m) 33 33 5 20 32 23 27 21 10 23 23 15 7 5 4 3 IN-SITU ANALYSIS Code Temperature Hydrolab Dissolved Oxygen Hydrolab In-situ measurements are collected monthly at the above locations at 1m intervals from 0.3m to 1m above bottom.

pH Hydrolab Measurements are taken weekly from July-August for striped bass habitat.

Conductivity Hydrolab NUTRIENT ANALYSES Ammonia AA-Nut Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/TB Q/T,B Q/T,B QrT QiT,B Q/T,B Q/T,B S/T Nitrate+Nitrite AA-Nut Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B . S/T Orthophosphate AA-Nut Q/T,B Q/T,B Q/T Qfr,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Total Phosphorus AA-TP,DG-P Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B QfT Q/T,B Q/T,B Q/T,B S/'"

Silica AA-Nut Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Cl AA-Nut Q/T,B Q/T,B Q/T Q/T,B Q/T,B Qf/,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T TKN AA-TKN Q/TB Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Total Organic Carbon TOC Q/T,B Q/T,B Q/T Q/T,B Qf/,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/TB S/T Dissolved organic carbon DOC Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/TB S/T ELEMENTAL ANALYSES Aluminum ICP-MS-D Q/T,13 S/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Calcium ICP-24 Q/T,B Q/TB Q/T Qf/,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Qf/,B S/T Iron ICP-MS-D Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Magnesium ICP-24 Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Qf/,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/"

Manganese ICP-MS-D Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Potassium 306-K Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Qf/,B Q/TB S/T Sodium ICP-24 Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Zinc (TR) ICP-MS-D Q/TB Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/TB Q/T Q/T,B Q/T,B Q/T,B S/T Arsenic (TR) ICP-MS-D Q/T,B Q/TB Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Cadminum (TR) ICP-MS-D Q/T,B Q/T,B Q/I" Qf/,B Q/T,B Q/f,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Copper (TR) ICP-MS-D Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/TB S/F Copper (Dissolved) ICP-MS Q/TB Q/T,B Q/T Q/T,B Qf/,B Q/TB Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/TB S/T Lead (TR) ICP-MS-D Q/T,B Q/T,B Q/r Q/T,B Q/T,B Q/T,B Qf/,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Selenium (TR) ICP-MS-D Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T ADDITIONAL ANALYSES Hardness Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/" Q/T,B Q/T,B Q/T,B S/T Alkalinity T-ALKT Q/T,B Q/T,B Q/T Q/TB Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Sf/

Turbidity F-TURD Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Sulfate UV_SO4 Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T Total Solids S-TSE Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/TB Q/T,B S/T Total Suspended Solids S-TSSE Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B Q/T,B Q/T,B Q/T Q/T,B Q/T,B Q/T,B S/T CODES: Frequency Q = Quarterly (Feb, May, Aug, Nov) S = Semi-annually (FebAug) T = Top (0.3m) B = Bottom (lm above bottom) TR= Total recoverable

Table 2-2. Analytical methods and reporting limits employed in the McGuire Nuclear Station NPDES Maintenance Monitoring Program for Lake Norman.

Parameter Method (EPA/APHA) Preservation Reporting Limit Alkalinity, Total Total Inflection Point, EPA 310.1 4 *C 0.01 meI/L Aluminum ICP, EPA 200.7 0.5% HNO 3 0.05 mg/L Cadmium, Total Recoverable ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 0.5 pg/L Calcium ICP, EPA 200.7 0.5% HNO 3 30 pg/L Chloride Colorimetric, EPA 325.2 4 "C 1.0 mg/L Copper, Total Recoverable ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 2.0 pg/L Copper, Dissolved ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 2.0 pg/L Iron, Total Recoverable ICP, EPA 200.7 0.5% HNO 3 10 pg/L Lead, Total Recoverable ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 2.0 pg/L Magnesium Atomic Emission/ICP, EPA 200.7 0.5% HNO 3 30 Ipg/L Manganese, Total Recoverable ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 1.0 pg/L Nitrogen, Ammonia Colorimetric, EPA 350.1 4 °C 20 pg/L Nitrogen, Nitrite + Nitrate Colorimetric, EPA 353.2 4 *C 20 pg/L Nitrogen, Total Kjeldahl Colorimetric, EPA 351.2 4 'C 100 pg/L Phosphorus, Orthophosphorus Colorimetric, EPA 365.1 4 *C 5 pg/L Phosphorus, Total Colorimetric, EPA 365.1 4 °C 5 pg/L Organic Carbon, Total EPA 415.1 0.5% H2SO4 0.1 mg/L Organic Carbon, Dissolved EPA 415.1 0.5% H2SO 4 0.1 mgiL Potassium ICP, EPA 200.7 0.5% HNO 3 250 pg/L Silica APHA 4500Si-F 0.5% HNO 3 500 pg/L Sodium Atomic Emission/ICP, EPA 200.7 0.5% HNO 3 1.5 mg/L Solids, Total Gravimetric, EPA 160.2 4 *C 0.1 mg/L Solids, Total Suspended Gravimetric, EPA 160.2 4 *C 0.1 mg/L Sulfate Ion Chromatography 4 *C 0.1 mg/L Turbidity Turbidimetric, EPA 180.1 4 *C 0.05 NTU Zinc, Total Recoverable ICP Mass Spectroscopy, EPA 200.8 0.5% HNO 3 1 pg/L

References:

USEPA 1983, and APHAI 1995 00

Table 2-3. Heat content calculations for the thermal regime in Lake Norman for 2005 and 2006.

2005 2006 Maximum Areal Heat Content (g-cal/cm2 ) 29,764 28,880 Minimum Areal Heat Content (g-cal/cm 2) 9,574 10,846 Birgean Heat Budget (g-cal/ cm 2) 20,190 18,034 Epilimnion (above 11.5 m) Heating Rate (0C /day) 0.123 0.091 Hypolimnion (below 11.5 m) Heating Rate (°C /day) 0.076 0.068 2-19

Table 2-4. A comparison of areal hypolinmetic oxygen deficits (AHOD), summer chlorophyll a (Chl a), Secchi depth, and mean depth of Lake Norman and 18 TVA reservoirs.

AHOD Summer Chl a Secchi Depth Mean Depth Reservoir (mg/cm 2 /day) (ug/L) (m) (m)

Lake Norman (2006) 0.037 4.3 2.2 10.3 TVA a Mainstem Kentucky 0.012 9.1 1.0 5.0 Pickwick 0.010 3.9 0.9 6.5 Wilson 0.028 5.9 1.4 12.3 Wheelee 0.012 4.4 5.3 Guntersville 0.007 4.8 1.1 5.3 Nickajack 0.016 2.8 1.1 6.8 Chickamauga 0.008 3.0 1.1 5.0 Watts Bar 0.012 6.2 1.0 7.3 Fort London 0.023 5.9 0.9 7.3 Tributary Chatuge 0.041 5.5 2.7 9.5 Cherokee 0.078 10.9 1.7 13.9 Douglas 0.046 6.3 1.6 10.7 Fontana 0.113 4.1 2.6 37.8 Hiwassee 0.061 5.0 2.4 20.2 Norris 0.058 2.1 3.9 16.3 South Holston 0.070 6.5 2.6 23.4 Tims Ford 0.059 6.1 2.4 14.9 Watauga 0.066 2.9 2.7 24.5 a Data from Higgins et al. (1980), and Higgins and Kim (1981) 2-20

0 0 0 Table 2-5. Quarterly surface (0.3 m) and bottom (bottom minus 1 m) water chemistry for the McGuire Nuclear Station discharge, mixing zone, and background locations on Lake Norman during 2005 and 2006. Values less than detection were assumed to be equal to the detection limit for calculating a mean.

Mixing Zone Mixing Zone MNS Discharge Mixing Zone Background Background LOCATION: 1.0 2

• 4.0 5.0 8.0 11.0 DEPTH: Surface Bottom Surface Bottom Surface Surface Bottom Surface Bottom Surface Bottom PARAMETERS YEAR: 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 Feb NA 1.6 NA 1.90 NA 1.80 NA 2.10 NA 1.50 NA 1.90 NA 2.00 1.6 2.10 2.3 1.70 2.2 2.20 2.8 3.00 May 1.10 1.4 0.98 1.20 1.2 1.80 1 1.30 1.2 1.30 1.3 1.20 1.2 1.60 1.4 1.40 1.1 1.20 1.1 1.50 1.5 1.80 Aug 10.00 1.7 20.00 1.30 9.8 1.70 18 1.70 22 1.70 9.8 1.60 9 4.00 1.4 1.40 1.7 1.60 1.9 1.80 1.8 2.50 Nov 2.00 1.1 3.3 3.30 2.40 1.30 2.70 1.70 3.70 1.20 5.30 1.80 4.90 1.60 2.30 3.20 6.50 1.10 3.70 1.20 7.00 3.60 Mean 4.37 1.45 8.09 1.9 4.47 1.7 7.23 1.7 8.97 1.4 5.47 1.6 5.03 2.3 1.68 2.0 2.90 1.4 2.23 1.7 3.28 2.7 Specific Annual Feb Conductance (umho/cm) 53.0 51 52.9 48 53.3 51 53.1 48 53.7 52 53.4 52 52.6 48 52.6 50 53.1 48 53.1 . 51 53.2 48 May 53.9 56 53.5 52 53.9 53 53.2 50 54.4 55 54.2 54 53.1 51 53.2 37 53.3 44 53.5 46 53.4 46 Aug 57.7 56 62.6. 58 58.2 56 67.4 61 58.4 56 58.2 56 65.9 61 58.0 56 59.9 56 58.2 57 64.1 58 Nov 57.7 55 57.8 55 57.8 55 57.7 75 58.5 56 58.0 55 58.3 55 58.0 55 57.8 52 56.6 54 56.7 51.0 Annual Mean 55.6 54.5 56.7 53.5 55.8 53.8 57.9 58.8 56.3 54.8 56.0 54.3 57.5 54.0 55.5 49.5 56.0 50.3 55.4 52.0 56.9 51.3 pH(anita)Feb 7.2 7.4 7.0 7.0 7.3 7.3 7.0 7.1 7.3 7.3 7.4 7.3 7.1 7.0 7.1 7.4 6.8 7.2 7.0 7.4 6.8 7.0 May 7.4 7.3 6.5 6.5 7.4 7.4 6.6 6.7 7.3 7.4 7.4 7.4 7.0 6.7 7.8 7.4 6.7 6.5 7.5 7.0 6.5 6.4 Aug 7.6 6.9 6.2 6.0 7.6 7.0 6.4 6.1 7.1 6.8 7.3 7.0 6.4 6.2 7.7 7.6 6.2 6.1 7.9 7.5 6.3 6.2 Nov 7.3 7.0 7.0 6.9 7.3 7.0 7.2 6.6 7.5 7.0 7.5 7.1 7.4 6.8 7.5 7.1 7.5 6.6 7.3 7.1 7.3 6.6 Annual Mean 7.37 6.66 6.66 6.60 7.37 7.18 6.80 6.63 7.29 7.10 7.39 7.20 6.96 6.68 7.52 7.38 6.79 6.60 7.42 7.25 6.73 6.55 Feb 12.5 11.5 12.0 11.5 11.5 11.5 12.5 11.5 12.5 11.0 12.0 11.5 12.0 11.5 12.5 13.5 12.5 11.5 12.0 12.0 12.5 12.0 May 12.0 12.5 12.0 12.5 12.5 12.5 12.5 12.5 13.0 12.5 12.5 12.5 12.5 12.5 12.0 12.5 12.5 12.5 12.5 13.0 12.5 13.0 Aug 14.0 13.5 15.5 14.0 14.0 14.0 16.0 14.0 14.0 13.5 14.0 14.0 19.5 17.5 14.0 14.5 15.5 14.5 14.5 14.5 17.5 15.0 Nov 14.5 14.5 15.0 16.0 15.0 12.5 15.0 FCC 14.5 14.0 15.0 FCC 13.0" 15.0 14.5 FOC 15.0 13.0 14.5 FQC 14.5 12.5 Annual Mean 13.3 13.0 13.6 13.5 13.3 12.6 14.0 12.7 13.5 12.8 13.4 12.7 14.3 14.1 13.3 13.5 13.9 12.9 13.4 13.2 14.3 13 .1 Feb 4.5 4.3 4.6 4.4 4.4 4.6 4.4 4.3 4.5 4.4 4.3 4.5 4.5 4.3 4.4 4.5 4.6 4.4 4.5 4.4 4.7 4.4 May 4.8 4.4 4.8 4.3 4.7 4.4 4.9 4.4 4.8 4.4 4.8 4.5 4.8 4.4 4.9 4.5 4.7 4.4 4.8 4.5 4.6 4.5 Aug 4.6 4.1 4.4 4.3 4.6 4.4 4.1 4.2 4.6 4.2 4.5 4.2 4.4 4.2 4.5 4.3 4.9 4.3 4.7 4.3 4.2 4.2 Nov 5.0 4.4 5.0 4.4 4.9 4.4 4.9 4.5 5.0 4.3 5.0 4.3 5.0 4.4 5.0 4.5 5.1 4.3 5.1 4.1 5.1 4.3 Annual Mean 4.7 4.3 4.7 4.4 4.7 4.5 4.6 4.4 4.7 4.3 4.7 4.4 4.7 4.3 4.7 4.5 4.8 4.4 4.8 4.3 4.7 4.4 Feb 4.3 4.2 4.3 4.5 4.4 4.3 4.2 4.3 4.3 4.4 4.3 4.3 5.1 4.2 4.3 4.7 4.2 5.3 4.4 4.3 4.2 4.2 May 4.7 4.4 4.7 4.4 4.7 4.4 4.7 4.4 4.7 4.4 4.7 4.5 4.7 4.7 4.7 4.5 4.6 4.4 4.6 4.4 4.4 4.3 Aug 4.2 4.2 4.0 4.5 4.2 4.2 4.0 4.5 4.2 4.2 4.2 4.3 3.8 4.5 4.2 4.4 3.7 4.5 4.1 4.3 3.9 4.5 Nov 4.1 3.9 4.0 4.0 4.2 6.0 4.2 3.9 4.1 4.0 4.1 4.1 5.0 4.0 4.2 4.0 4.1 4.0 4.0 4.0 4.0 4.0 Annual Mean 4.3 4.2 4.3 4.4 4.3 4.7 4.3 4.3 4.3 4.3 4.3 4.3 4.6 4.4 4.4 4.4 4.1 4.6 4.2 4.3 6.7 4.3 Feb 2.96 2.96 2.96 3.07 2.95 2.96 2.94 3.09 2.97 2.99 2.96 2.95 2.97 2.97 2.97 3.15 3.02 3.29 3.07 3.20 3.'15 3.11 May 3.02 3.35 3.05 3.65 3.02 3.31 3.04 3.53 3.01 3.44 3.00 3.35 3.02 3.33 3.00 3.33 3.09 3.81 3.08 3.47 3.17 3.51 Aug 3.08 3.45 3.43 3.54 3.10 3.19 3.51 3.71 3.12 3.51 3.11 3.15 3.64 3.84 3.11 3.29 3.49 3.69 3.18 3.52 3.54 3.71 Nov 3.17 3.06 3.11 3.08 3.17 3.05 3.17 3.15 3.16 3.04 3.15 3.15 3.14 3.07 3.15 3.06 3.08 2.44 3.02 2.94 3.06 2.46 Annual Mean 3.06 3.21 3.14 3.34 3.06 3.13 3.17 3.37 3.07 3.25 3.06 3.15 3.19 3.30 3.06 3.21 3.17 3.31 3.09 3.28 3.23 3.20 Feb 1.51 1.33 1.51 1.33 1.51 1.32 1.49 1.37 1.52 1.33 1.52 1.32 1.52 1.32 1.52 1.35 1.51 1.31 1.51 1.35 1.50 1.32 May 1.48 1.40 1.48 1.42 1.47 1.40 1.48 1.42 1.48 1.41 1.47 1.41 1.48 1.41 1.47 1.40 1.48 1.41 1.47 1.42 1.49 1.45 Aug 1.58 1.41 1.61 1.44 1.59 1.39 1.64 1.45 1.59 1.40 1.58 1.39 1.69 1.53 1.58 1.40 1.64 1.47 1.59 1.44 1.65 1.49 Nov 1.71 1.52 1.70 1.52 1.71 1.52 1.71 1.53 1.70 1.52 1.71 1.52 1.70 1.71 1.71 1.52 1.71 1.47 1.69 1.51 1.71 1.47 Annual Mean 1.57 1.42 1.58 1.43 1.57 1.41 1.58 1.44 1.57 1.42 1.57 1.41 1.60 1.49 1.57 1.42 1.59 1.42 1.57 1.43 1.59 1.43 k)

NS = Not Sampled: NA= Not Applicable; FQC = Failed Quality Control

Table 2-5 (Continued)

Mixing Zone Mixing Zone MNS Discharge Mixing Zone Background Background LOCATION: 1.0 2 4.0 5.0 8.0 11.0 DEPTH: Surface Bottom Surface Bottom Surface Surface

• Bottom Surface Bottom Surface Bottom PARAMETERS YEAR: 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 Potassium (mg/L)

Feb 1.79 1.74 1.80 1.71 1.80 1.72 1.78 1.60 1.82 1.74 1.83 1.70 1.79 1.69 1.80 1.64 1.75 1.70 1.75 1.65 1.67 1.64 May 1.70 1.61 1.71 1.63 1.69 1.64 1.69 1.63 1.67 1.62 1.69 1.66 1.71 1.64 1.69 1.62 1.66 1.60 1.63 1.47 1.61 1.55 Aug 1.72 1.56 1.73 1.60 1.70 1.54 1.73 1.57 1.72 1.55 1.72 1.53 1.76 1.63 1.72 1.54 1.71 1.61 1.68 1.54 1.73 1.61 Nov 1.87 1.74 1.89 1.72 1.86 1.71 1.87 1.74 1.86 1.72 1.87 1.74 1.87 1.73 1.89 1.74 1.91 1.84 1.95 1.77 1.95 1.85 Annual Mean 1.77 1.66 1.78 1.67 1.76 1.65 1.77 1.64 1.77 1.66 1.78 1.66 1.78 1.67 1.78 1.64 1.76 1.69 1.75 1.61 1.74 1.66 Sodium (mg/L)

Feb 4.65 4.37 4.66 4.30 4.63 4.37 4.60 4.40 4.67 4.38 4.66 4.33 4.64 4.28 4.64 4.16 4.67 4.33 4.69 4.20 4.62 4.12 May 4.51 4.42 4.49 4.41 4.51 4.40 4.48 4.37 4.49 4.41 4.51 4.40 4.57 4.29 4.51 4.39 4.46 4.34 4.502 4.55 4.417 4.43 Aug 4.84 4.41 4.53 4.27 4.85 4.34 4.53 4.29 4.82 4.36 4.83 4.32 4.61 4.39 4.82 4.36 4.56 4.34 4.383 4.39 4.537 4.33 Nov 5.27 4.42 5.27 4.44 5.24 4.41 5.26 4.43 5.27 4.42 5.26 4.42 5.25 4.43 5.26 4.42 5.28 4.42 5.36 4.39 5.38 4.40 Annual Mean 4.81 4.41 4.74 4.36 4.81 4.38 4.72 4.37 4.81 4.39 4.81 4.37 4.77 4.35 4.81 4.33 4.74 4.36 4.73 4.38 4.74 4.32 Aluminum (mg1L)

Feb 0.050 0.055 0.056 0.050 0.050 0.063 0.050 0.051 0.050 0.050 0.050 0.050 0.060 0.064 0.050 0.062 0.057 0.050 0.050 0.050 0.050 0.071 May 0.055 0.050 0.050 0.053 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.071 0.050 0.050 0.050 0.055 0.050 0.050 0.050 0.065 Aug 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 Nov 0.050 0.050 0.050 0.054 0.050 0.050 0.050 0.050 0.050 0.056 0.050 0.050 0.050 0.055 0.050 0.050 0.050 0.144 0.050 0.055 0.050 0.158 Annual Mean 0.051 0.052 0.052 052 0.050 0.053 0.050 0.050 0.050 0.052 0.050 0.050 0,053 0.060 0.050 0.053 0.052 0.075 0.0500 0.051 0.050 0.086 Iron (mg/L)

Feb 0.118 0.100 0.245 0.150 0.124 0.100 0.237 0.190 0.138 0.120 0.123 0.110 0.315 0.150 0.132 0.110 0.281 0.130 0.202 0.110 0.278 0.210 May 0.050 0.100 0.077 0.120 0.061 0.100 0.074 0.100 0.054 0.100 0.061 0.100 0.064 0.160 0.051 0.100 0.106 0.100 0.049 0.100 0.142 0.250 Aug 0.040 0.100 0.063 0.100 0.036 0.100 0.260 0.100 0.049 0.100 0.042 0.100 0.556 0.300 0.032 0.100 0.098 0.100 0.052 0.100 0.110 0.100 Nov 0.115 0.098 0.201 0.172 0.121 0.105 0.119 0.243 0.113 0.086 0.106 0.094 0.232 0.150 0.087 0.074 0.318 0.226 0.147 0.075 0.324 0.279 Annual Mean 0.081 0.100 0.147 0.136 0.086 0.101 0.173 0.158 0.089 0.102 0.083 0.101 0.292 0.190 0.076 0.096 0.201 0.139 0.113 0.096 0.214 0.210 Manganese (ug/L)

Feb 17 15 51 40 18 15 71 35 17 16 17 Is 48 32 14 16 42 14 28 20 57 30 May 9 7 33 23 8 14 33 17 8 8 8 7 9 36 6 6 30 19 8 10 54 34 Aug 23 19 1079 502 23 19 1584 264 48 28 34 23 2038 1337 20 13 838 522 33 16 1550 - 868 Nov 44 71 54 274 43 81 42 484 41 68 45 73 89 188 31 50 55 294 56 41 101 201 Annual Mean 23 28 304 210 23 32 433 200 29 30 26 30 546 398 18 21 241 212 31 22 441 283 Cadmium (ug(L)

Feb 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 May 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Aug 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Nov 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Annual Mean 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Copper (ug/L)

Feb 2.0 2.0 2.1 . 2.2 2.0 2.0 2.2 2.1 . 2.0 2.1 2.5 2.1 2.1 2.1 2.0 2.7 2.1 2.0 2.5 3.0 2.1 2.3 May 2.0 2.0 2.1 2.2 ý.o 2.0 2.0 2.0 2.0 2.3 2.0 2.0 2.0 2.0 2.0 2.3 2.0 2.3 2.5 3.3 2.0 2.4 Aug 2.1 2.0 2.0 2.0 2.1 2.0 2.0 2.0 2.1 2.0 2.2 2.0 2.0 2,0 2.0 2.0 2.0 2.0 2.8 2.9 2.0 2.0 Nov 2.0 2.3 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2,0 2.0 , 2.0 2.0 2.0 2.0 2.2 2.8 5.2 2.8 2.3 Annual Mean 2.0 2.1 2.1 2.1 2.0 2.0 2.1 2.0 2.0 2.1 2.2 2.0 2.0 2.0 2.0 2.3 2.0 2.1 2.7 3.6 2.2 2.3 Lead (ug/L)

Feb 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 May 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Aug 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Nov 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Annual Mean 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 NS = Not Sampled: NA= Not Applicable; FQC = Failed Quality Control h.)

0 Table 2-5 (Continued)

Mixing Zone Mixing Zone MNS Discharge Mixing Zone Background Background LOCATION: 1.0 2.0 4.0 5.0 8.0 11.0 DEPTH: Surface Bottom Surface Bottom Surface Surface Bottom Surface Bottom Surface Bottom PARAMETERS YEAR: 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 2006 2005 Zinc (ug/L)

Feb 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.4 1.0 1.0 1.0 1.0 1.0 1.0 1.0 4.1 1.0 1.1 1.0 1.1 1.0 May 1.0 1.0 1.0 1.4 1.0 1.1 1.0 1.5 1.0 8.0 1.0 1.2 1.0 5.8 1.0 1.0 1.0 2.1 5.6 1.0 1.0 1.5 Aug 1.8 1.0 1.1 1.0 1.4 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.2 1.0 1.0 1.0 2.7 1.0 1.0 1.0 Nov 4.7 3.4 1.1 1.7 2.0 1.5 1.0 1.6 1.0 5.3 1.0 1.0 1.0 1.8 1.0 1.5 1.0 1.7 1.0 3.3 1.2 1.6 Annual Mean 2.1 1.6 1.1 1.3 1.4 1.2 1.0 1.3 1.1 3.8 1.0 1.1 1.0 2.4 1.0 1.1 1.8 1.5 2.6 1.6 1.1 1.3 Nitrite-Nitrate (ug/L)

Feb 200 270 230 270 210 260 220 270 200 270 200 280 210 270 210 270 240 310 260 330 310 180 May 200 240 290 290 210 240 280 290 210 240 210 250 210 290 190 230 290 290 190 230 290 300 Aug 50 130 530 320 60 130 240 350 110 160 90 150 120 210 50 80 220 310 40 70 200 300 Nov 150 130 300 570 90 120 140 80 180. 100 120 130 110 120 130 130 140 230 160 260 390 290 Annual Mean 150.0 192.5 337.5 362.5 142.5 187.5 220.0 247.5 175.0 192.5 155.0 202.5 162.5 222.5 145.0 177.5 222.5 285.0 162.5 222.5 297.5 267.5 Ammonia (ug/L)

Feb 120 60 140 100 84 30 110 60 87 40 86 30 120 70 110 20 98 70 85 30 100 40 May 35 20 40 70 30 20 38 60 35 30 31 20 28 60 24 20 45 70 35 30 56 90 Aug 90 90 150 120 80 90 170 80 92 90 90 60 200 130 84 40 120 100 100 230 140 100 Nov 65 130 65 120 65 80 63 140 63 80 69 75 69 110 60 77 56 340 56 82 73 130 Annual Mean 77.5 75.0 98.8 102.5 64.8 55.0 95.3 85.0 69.3 60.0 69.0 46.3 104.3 92.5 69.5 39.3 79.8 145.0 69.0 93.0 92.3 90.0 Total Phosphorous (ug/L)

Feb 7 10 9 10 8 10 9 10 8 10 10 10 9 10 9 10 10 10 14 10 May 8 10 8 10 8 .10 7 9 7 10 7 11 7 11 7 11 8 10 7 15 9 14 Aug 7 9 8 11 7 11 10 9 7 11 7 11 6 11 7 11 7 10 8 12 8 12 Nov 8 8 11 8 9 10 9 8 9 7 8 7 9 8 8 7 12 16 10 9 15 16 Annual Mean 7.5 9.3 9.0 9.8 8.0 10.3 8.8 9.0 7.8 9.5 7.5 9.8 8.5 10.0 7.8 9.8 9.0 11.5 8.8 11.5 11.5 13.0 Orthophosphate (ug/L)

Feb 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 May 5 5 5 5 5 5 5 5 9 5 5 5 5 5 5 5 5 5 5 5 6 5 Aug 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Nov 5 5 5 5 5 5 13 5 5 5 5 5 6 5 5 5 5 5. 5 5 5 5 Annual Mean 5.0 5.0 5.0 5.0 5.0 5.0 7.0 5 6.0 5 5.0 5 5.3 5 5.0 5 5.0 5 5.0 5.0 5.3 5 Silicon (mg/L)

Feb 4.6 4.7 4.6 4.8 4.6 4.7 4.6 4.8 4.5 4.7 4.5 4.8 4.6 4.8 4.5 4.8 4.6 4.7 4.4 4.9 4.6 4.9 May 4.5 4.2 4.8 4.7 4.5 4.2 4.8 4.6 4.5 4.3 4.4 4.3 4.5 4.7 4.4 4.1 4.9 4.6 4.2 4.1 4.8 4.7 Aug 4.0 3.7 5.5 4.9 4.1 3.8 5.5 4.9 4.1 3.9 4.1 3.8 5.4 4.7 4.1 3.6 5.4 4.8 4.1 3.9 5.3 4.9 Nov 4.6 4.6 4.4 4.7 4.4 4.7 4.4 4.8 4.4 4.7 4.4 4.7 4.5 4.7 4.4 4.7 4.3 5.3 4.6 4.8 4.5 5.3 Annual Mean 4.4 4.3 4.8 4.8 4.4 4.4 4.8 4.8 4.4 4.4 4.4 4.4 4.8 4.7 4.4 4.3 4.8 4.9 4.3 4.4 4.8 5.0 NS = Not Sampled: NA= Not Applicable; FQC = Failed Quality Control

80 69 A

N Miles Kilometers 0 2 4 I

8. 1.5 1.0 -

4.0 Figure 2-1. Water quality sampling locations (numbered) for Lake Norman. Approximate locations of Marshall Steam Station, and McGuire Nuclear Station are also shown.

2-24

180 70 16 ___ 60 16060 140 50 120 f2 40

.D100 E

800 680- - - - -30 60 -

20 40 - - -

10 20 0 0 6; 6- N- N-6; -- - - - 0 o O Figure 2-2a. Annual precipitation totals in the vicinity of McGuire Nuclear Station.

20 208 02005 U20061 18 _______

16 14 12 12 -

0-JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 2-2b. Monthly precipitation totals in the vicinity of McGuire Nuclear Station in 2005 and 2006.

2-25

0 30 28 26 24 22 20 42U 18 16 14 12 10 8

6 4

2 0

Jan Feb .Mar .Apr May Jun Jul Aug Sep Oct Nov Dec S-0<>- Long-term average - -A- 2005 -UN- 2006 Figure 2-2c. Mean monthly air temperatures recorded at McGuire Nuclear Station beginning in 1989. Data were complied from k) average daily temperatures which, in turn, were created from hourly measurements.

JAN FEB MAR Temperature ('C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 15 Q

-20 APR MAY JUN Temperature ('C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0

5 10

&15

-20 25 30 35 b*

Figure 2-3. Monthly mean temperature profiles for the McGuire Nuclear Station background zone in 2005 (**) and 2006 (xx).

0 JUL AUG SEP Temperature ('C) Temperature ('C) Temperature (*C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 E15-

-20 Q

OCT NOV DEC Temperature ('C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0

5 10

-20 25 30 35 1 35 Figure 2-3. (Continued).

00

JAN FEB MAR Temperature ('C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 a 5 10 15 20 25 30 35 0 5 o' f5 20 25 30 35 0

5 10 10 E 15 E 15 220 -20 25 25 30 30 35 APR MAY JUN Temperature ('C) Temperature (°C) Temperature ('C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 0 0 5 2 5 5 5

.2- . 2-'

10 " 10 '10 x.X "X

Eg15 Ei15

.20- -20 w20 25 25 25 30 2 30 30 35 35 35 t'J Figure 2-4. Monthly mean temperature profiles for the McGuire Nuclear Station mixing zone in 2005 (**) and 2006 (xx).

t'o

0 0 JUL AUG SEP Temperature (C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 a 5 fo 15 20 25 30 35 0 5 o0 f5 20 25 30 35 E15 Q

-20 OCT NOV DEC Temperature ('C) Temperature ('C) Temperature ('C) 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 5.

E 10 20 25 30 0

Figure 2-4. (Continued).

40 35 30

., 25

-20 I- 10 El a) 10 5-0-

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 11 10 9 ".0

-J E 8-7

• 6 0 5

> 4 Cn 3-5 2-CI 1

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Figure 2-5. Monthly surface (0.3m) temperature and dissolved oxygen data at the discharge location (Location 4.0) in 2005 (0) and 2006 (0).

2-31

JAN FEB MAR Dissolved Oxygen (mgIL) Dissolved Oxygen (mg/L) Dissolved Oxygen (mgIL) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 5

10 E15

• 20 25 30 35 APR MAY JUN Dissolved Oxygen (mg/L) Dissolved Oxygen (mgIL) Dissolved Oxygen (mg/L) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 5 5 .. 5 x 10 10 10 22 -2 .20 A

E 15 615 X, *15 E*

X.

25 25 25-xx 30 230 - 10 35 2 35 35 Figure 2-6. Monthly mean dissolved oxygen profiles for the McGuire Nuclear Station background zone in 2005 and 2006 (xx).

bo

0 JUL AUG SEP Dissolved Oxygen (mgIL) Dissolved Oxygen (mg/L) Dissolved Oxygen (mgIL) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 0 5 x 5 10 10 .

.0 2015-25 25 30 30 35 35 35 30 OCT NOV DEC Dissolved Oxygen (mgIL) Dissolved Oxygen (mg/L) Dissolved Oxygen (mgJL) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 . . . . ] . . . . I . . . . I , I ]

'C 5

5-10 10 -

-20o .0

• 0 25 0 25 30 30 35 Figure 2-6. (Continued).

0 JAN FEB MAR Dissolved Oxygen (mg/L) Dissolved Oxygen (mg/L) Dissolved Oxygen (mg/L) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0

5 10 E 15

-20 25 30 35

. APR MAY JUN Dissolved Oxygen (mg/L) Dissolved Oxygen (mg/L) Dissolved Oxygen (mg/L) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0

5 10 10 S15 15 w20 v 20 25 25 30 30 35 35 35 Figure 2-7. Monthly mean dissolved oxygen profiles for the McGuire Nuclear Station mixing zone in 2005 (**) and 2006 (xx).

JUL AUG SEPT Dissolved Oxygen (mg/L) Dissolved Oxygen (mgIL) Dissolved Oxygen (mg/L) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 iv *.... .. I... .... I....I...

5- 5-215 10-215-

,XX X X 10 E15- ....

-20 -20 )Ik 20-Q 25 25 30 30 3* 3b OCT NOV DEC Diksolved Oxygen (mg/L) Dissolved Oxygen (mg/L) Dissolved Oxygen (ragIL) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 Figure 2-7. (Continued).

22O: 22 8 21 1215&

11 210- 21 20& 205 200 Temperature (deg C) 20 Jan 4, 2006 195 ... I 9...........................

i .

0 5 10 15 20 25 30 35 40 45 50 55 0 5 Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (km) 240 240 Sampling Locations 235 1.o 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 .0 23&- 1.0 230 230- 4

~2250 22&_

220 0:

8 21 8 215-2117 21(-

205- 205-20:Temperature (deg C)2 Mar 8, 2006 195 .. 5. . '. .10

. . .. .=. . .. . . ..

.= .=.. . . . .. .

.= ...

.= . .1 .. .50 . . O 5 0 5 10 15 20 25 30 35 40 45 50 1535 0 5 Distance from Cowans Ford Dam (kin) Distance from Cowana Ford Dam (kin)

Figure 2-8. Monthly reservoir-wide temperature isotherms for Lake Norman in 2006.

240 240 Sampling Locations Sampling Locations 235- 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 235- 1.0 8-0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 23--- 22- NS 230-3 EE 215 2151 210_ 210" 214 20&: 205" 20&: Temperature (deg C) 20: Temperature (deg C)

May 3, 2006 Jun 7, 2006

19. ... ... ... ... ... ... 19......

9 ,...... ............. I I ... ...... ...

0 5 10 15 20 25 30 35 40 45 50 55 0 5 10 15 20 25 30 3 .... 410 .45 50 55 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin) 240 24 Sampling Locations Sampling Locations 235" 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 o0.0 235- 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 2222 225 28 3 278

~21 & _ _ _ __ _ _ _ _2 F3__21__ ___

8210-2 20 Temperature (deg C) 20-: Temperature (deg C) 195 .....

Jul 5, 2006 Aug 7, 2006

• . ... ...... ......... . .. .... .. ', 195"* ' .. . . - . .9 0 5 10 15 20 25 30 35 40 45 '50 5 0 5 10 15 20 25 30 . 35 40 4'5 50 55 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin)

Figure 2-8. (Continued).

0 0 240-Sampling Locations 23- 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 4

I 4 4 4 4 4 1 4 4 2302 225 E 2201 .

E 215 2101 205-

• 20 Temperature (deg C).

Sep11, 2006 0 5 10 15 20 25 30 35 40 45 50 55 Distance from Cowans Ford Dam (kmn) Distance from Cowans Ford Dam (kin)

Sampling Locations 235- 1.0 I

8.0 I

11.0 I4 13.0

.4 15.0 15.9 1

62.0 14 69.0 1

72.0 80o 230-225-

~220-8 215-I 210 205-200- Temperature (deg C)

Nov 6, 2006 U A.... 11 .... 5 ' 210.... 25 ....

A 3`0 .... 35 .... 40 ... 4V. . . 5'5 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin) 00 Figure 2-8. (Continued).

0 240 -

Sampling Locations Sampling Locations 235- 1.0

.11 8.0 1,

11.0 13.0 15.0

,L 15.9 1,

62.0 1,L 69.0 72.0 I

80.0 I

235- 1.0 I

8.0 4

11.0 4

13.0 1

15.0 15.9 62.0 1 ,

69.0 I

72.0 80o0 230- 230-225- 10 225-220- S220-215- 5 215-210-210-205- 205-200- Dissolved Oxygen (mg/L) 200- Dissolved Oxygen (mg/L)

Jan 4, 2006 Feb 7, 2006 1 s.................................10 ... ...... ..................... 195q I .

i . . . P.

.i 10 15 20 25 30 35 40 45 50 .55 51 101. .. 15 152. i. . 2

.2025305 i ..... . 0 .. .........

3 0 40D45( .....

45- - ........

- - d Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin)

Sampling Locations 23& 1.0 5.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 44 .4 4 225-S220-

-8 ©o0 5 215-5]

210 0~

205-200-Dissolved Oxygen (mg/L)

Apr 5, 2006 19-, .. . ..... ........ .... .... .. . ....

6 * ----1'o 15 20 25 30 35 40 45 50 55 Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (km)

Figure 2-9. Monthly reservoir-wide dissolved oxygen isopleths for Lake Norman in 2006.

240 240 Sampling Locations Sampling Locations 235- 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 .72.0 0.0 235 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 60.0 230- 230-J 9 '

r 221 711P22 8 215-. 8 215 215- 21&--

20& 205) 200-_ Dissolved Oxygen (mg/L) 20 Dissolved Oxygen (mg/L)

May 3, 2006 1 Jun 7, 2006 0 5 10 15 20 25 30 35 40 45 50 55 0 5 10 15 20 25 30 35 410 .... 45' 50 55 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin) 240 240-Sampling Locations Sampling Locations 235 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 90.0 23&- 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0

'23& 0 -8 -

230-225 22 15 2208 222:

21 25 10 210 C) 21o 205 20&

200 . Dissolved Oxygen (mg/L) 200 Dissolved Oxygen (mg/L)

Jul 5, 2006 ... 'o.. .. . 19'1 .. .. Aug 7, . 2006 195 , . .. ..... 5 ' ' '30 ' ' 's. . .4........ ...

0 0 15 20 25 30 35 40 45 50 55 0 5 10 15 20 25 30 35 40 45 50 55 Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (km)

Figure 2-9. (Continued).

0 0 0 240. 240 Sampling Locations Sampling Locations 235 1.0) 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 235 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 230-I 46 ' 4 23

• 2" 220 20j Dissolved Oxygen (mg/L) 20o Dissolved Oxygen (rag/L)

Sepll1,2006 . Oct 3, 2006 0 5 10 15 20 25 30 35 40 45 50 55 0 5 10 15 20 25 30 35 40 45 50 55 Distance from Cowans Ford Dam (kin) :Distance from Cowans Ford Dam (kin) 00 S215"& 215-5 21 240~

21, 240-21 &

Sampling Locations Sampling Locations .

235 1. 80 11. 1.0.. 19.0 15.9* 62.0 69.0, 72.0 8o.0 23. 1.0 205 8.0 11.0 13.0 15.015.9 62.0 69.0 72.0 80.0 205, 22 22 200 Dissolved Oxygen (mg/L) 200 Dissolved Oxygen (mg/L)

Nov 6, 2006 Dec 5, 2006 19 5 . . . . , . . , . , . . . . . .. . .3'0 . . . . . . . . . , . . .. ' . . . . I I 1-'i 195 ........ ... . . . . .. . ..

0 5 10 15 20 25 30 35 40 45 50 55 10 15 20 25 30 35 40 45 50 55 Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (kin)

.mlnFigure 2-9. (Continued).

35 30 25 E

q 20 0*

M 15 10 5

0 0 50 100 150 200 250 300 350 Julian Date Figure 2-10a. Heat content of the entire water column (i) and the hypolimnion (o) in Lake Norman in 2006.

12- 100 90 10 2 80 C

70 0 8

I...

60 6 50 -I-C 40 4 a, 30 C-20 2

10 0 0 1 31 61 91 121 151 181 211 241 271 301 331 361 Julian Date Figure 2-1Ob. Dissolved oxygen content (-) and percent saturation (---) of the entire water column (0) and the hypolimnion (o) of Lake Norman in 2006.

2-42

Z4 I LAKE NORMAN STRIPED BASS HABITAT iLAKE NORMAN STRIPED BASS HABITAT 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 23 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 23 1.0 230*...

230 26 deg C 26 deg C 2 2 mg/L 21 215- 2 mg/L C321O:[

2o5 Jun 7, 2006 2o Jun 28, 2006 200304 20

.10 A... 2!0 .... :1 1' 51 A0 41'5 50 55 .... A 10" 1,5 2'5 3'0 3Z5 410 75 - se-Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (km) 4-240.

LAKE NORMAN STRIPED BASS HABITAT i . LAKE NORMAN STRIPED BASS HABITAT!

8.0 11.0 13.0 15.0 15.9 82.0 69.0 72.0 80.0 23 1.0 8.0 11.0 13.0 15.0 15.9 620 89.0 72.0 80.0 23 1.0 230 230-22o- 22.

26 deg C 2 rmg/,

~/ m 01 215 m8 21*1 26 deg C FEKE/:O 20 Jul 5, 2006 2Jul 19, 2006 20 205:

1 b . .A. . 0' '5. . 7- W - -g . .3 1 11195 . . ~ '1 19 . . .. go 7

.20 40 25 30 35 4 45 55 Distance from Cowans Ford Dam (km) Distance from Cowans Ford Dam (km)

Figure 2-11. Striped bass habitat (shaded areas; temperatures S 26 'C and dissolved oxygen > 2 mg/L) in Lake Norman in June, July, August, September, and October 2006.

?I 26 deg C

• t " *' /2mg/L

~215 2ot:2; * . Aug 1, 2006 119. .... 10 ..... 2.... 310 . 315 .. W .... 500 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (kin) 24G LAKE NORMAN STRIPED BASS HABITAT 23 1.0 8.0 11.0 13.0 15.0 15.9 62.0 69.0 72.0 80.0 23 E2 26 deg C 2 2 mg/L 21* M 2o0: Sep 11, 2006 20o 19 9 . . 1 5 1 ,7 Distance from Cowans Ford Dam (kin) Distance from Cowans Ford Dam (KM)

S Figure 2-11. (Continued).

232.0 Full Pond @ 231.65 mmsl 231.5 231.0

- 230.5 230.0 229.5 0 0 0 0 0 0 Figure 2-12. Lake Norman lake levels, expressed in meters above mean sea level (mmsl) for 2002, 2003, 2004, 2005, and 2006. Lake level data correspond to the water quality sampling dates over this time period.

L*

CHAPTER 3 PHYTOPLANKTON INTRODUCTION Phytoplankton standing crop parameters were monitored in 2006 in accordance with the NPDES permit for McGuire Nuclear Station (MNS). The objectives of the phytoplankton study of the Lake Norman Maintenance Monitoring Program are to:

1. Describe quarterly patterns of phytoplankton standing crop and species composition throughout Lake Norman; and

2. Compare phytoplankton data collected during this current study with data collected in prior study years.

In previous studies on Lake Norman considerable spatial and temporal variability in phytoplankton standing crops and taxonomic composition have been reported (Duke Power Company 1976, 1985; Menhinick and Jensen 1974; Rodriguez 1982). Rodriguez (1982) classified the lake as oligo-mesotrophic (low to intermediate productivity) based on phytoplankton abundance, distribution, and taxonomic composition. Past maintenance monitoring program studies have confirmed this classification.

METHODS AND MATERIALS Quarterly sampling was conducted at Locations 2.0, 5.0 (Mixing Zone), 8.0, 9.5, 11.0, 13.0, 15.9, and 69.0 in Lake Norman (Figure 2-1). Duplicate grabs from 0.3, 4.0, and 8.0 m (i.e.,

the estimated euphotic zone) were taken and then composited at all locations except Location 69.0, where grabs were taken at 0.3, 3.0, and 6.0 m due to the depth. Grab samples were composited for each location. Sampling was conducted in February, May, August, and November 2006. Secchi depths were recorded from all sampling locations. As in previous years and based on the original design study (Duke Power Company 1988), phytoplankton density, biovolume, and taxonomic composition were determined for samples collected at Locations 2.0, 5.0, 9.5, 11.0, and 15.9; chlorophyll a concentrations and seston dry and ash-free dry weights were determined for samples from all locations. Chlorophyll a and total 3-1

phytoplankton densities and biovolumes were used in determining phytoplankton standing crop. Field sampling and laboratory methods used for chlorophyll a, seston dry weights, and population identification and enumeration were identical to those used by Rodriguez (1982).

Data collected in 2006 were compared with corresponding data from quarterly monitoring beginning in August 1987.

RESULTS AND DISCUSSION Standing Crop Chlorophyll a Chlorophyll a concentrations (mean of two replicate composites) ranged from a low of 1.43 ptg/L at Location 2.0 in February, to a high of 15.05 gig/L at Location 8.0 in November (Table 3-1, Figure 3-1). All values were below the North Carolina water quality standard of 40 jtg/L (NCDENR 1991). Lake-wide mean chlorophyll concentrations during all but February were within ranges of those reported in previous years, while the lake-wide mean in February was the lowest yet recorded for this month (Figure 3-2). Based on quarterly mean chlorophyll concentrations, the trophic level of Lake Norman was in the oligotrophic (low) range during February and May and in the mesotrophic (intermediate) range in August and November 2006. About 56% of the mean chlorophyll a values were less than 4 ýtg/L (oligotrophic),

while just over 93% of the remaining chlorophyll a values were between 4 and 12 tg/L (mesotrophic). The chlorophyll concentration from Location 8.0 in November was the only one greater than 12 ptg/L (eutrophic, or high range). Historically, quarterly mean concentrations of below 4 ýtg/L have been recorded on twelve previous occasions, while lake-wide mean concentrations of greater than 12 tg/L were only recorded during May of 1997 and 2000 (Duke Power 1998, 2001).

During 2006 chlorophyll a concentrations showed a certain degree of spatial variability.

Maximum concentrations among sampling locations were observed at Location 15.9 in February, Location 69.0 during May and August, and at Location 8.0 in November (Table 3-1). Minimum concentrations occurred at Location 2.0 in all months but November, when Location 69.0 had the lowest chlorophyll concentration (Table 3-1). The trend of increasing chlorophyll concentrations from down-lake to up-lake, which had been observed during many previous years, was apparent during all but November (Table 3-1, Figure 3-1).

3-2

Flow in the riverine zone of a reservoir is subject to wide fluctuations depending, ultimately, on meteorological conditions (Thornton, et al. 1990), although influences may be moderated due to upstream dams. During periods of high flow, algal production and standing crop would be depressed due in great part to washout. Conversely, production and standing crop would increase during periods of low flow and high retention time. However, over long periods of low flow, production and standing crop would gradually decline once more. These conditions result in the comparatively high variability in chlorophyll concentrations observed between Locations 15.9 and 69.0 throughout many previous years, as opposed to Locations 2.0 and 5.0 which have usually shown similar concentrations during sampling periods.

Mean quarterly chlorophyll concentrations during the period of record (August 1987-November 2006) have varied considerably, resulting in moderate to wide historical ranges (Figure 3-2). During February 2006, chlorophyll values at all but Locations 13.0 and 69.0 were the lowest yet recorded for February (Figure 3-3). Chlorophyll concentrations at Locations 13.0 and 69.0 were in the low and mid historical ranges, respectively. Long-term February peaks at Locations 2.0 through 9.5 occurred in 1996, while the long-term February peak at Locations 11.0 and 15.9 were observed in 1991 and 2003, respectively. The highest February value at location 69.0 occurred in 2001. All but Location 69.0 had lower chlorophyll concentrations in February 2006 than in February 2005 (Duke Energy 2006).

During May, mean chlorophyll concentrations at all locations were in the low historical range (Figure 3-3). Long-term May peaks at Locations 2.0 and 9.5 occurred in 1992; at Location 5.0 in 1991; at Locations 8.0, 11.0, and 13.0 in 1997; at Location 15.9 in 2000; and at Location 69.0 in 2001. May 2006, mean chlorophyll concentrations at all locations were lower than those of 2005 (Duke Energy 2006).

August 2006 mean chlorophyllI concentrations at Locations 2.0, 8.0, and 13.0 were the lowest August concentrations yet recorded for these locations. Locations 9.5, 11.0, and 15.9 were in the low historical range, while Locations 5.0 and 69.0 were in the mid range (Figure 3-4).

Long- term August peaks at Locations 2.0 and 5.0 were observed in 1998, while August peaks at Locations 8.0 and 9.5 occurred in 1993. Long-term August peaks at Locations 11.0 and 13.0 were observed in 1991 and 1993, respectively. The highest August chlorophyll concentration from Location 15.9 was observed in 1998, while Location 69.0 experienced its long-term August peak in 2001. At Locations 5.0 and 69.0, August 2006 chlorophyll 3-3

concentrations were higher than in August 2005, while August concentrations at all other locations were lower than those of the previous year (Duke Energy 2006).

During November 2006, the highest chlorophyll concentrations ever observed for a November period were recorded from Locations 5.0 and 8.0 (Figure 3-4). At Locations 2.0, 9.5, 11.0, and 13.0, chlorophyll concentrations were in the high historical range, while values from Locations 15.9 and 69.0 were in the intermediate and low ranges, respectively. Long-term November peaks at Locations 5.0 and 8.0 occurred in 2006, while November maxima at Locations 11.0 through 15.9 occurred in 1996. The November maximum at Locations 2.0 and 9.5 were observed in 1997. The highest November chlorophyll concentration at Location 69.0 occurred in 1991. November 2006 chlorophyll concentrations at all but Location 69.0 were higher than during November 2005 (Duke Energy 2006).

Total Abundance Density and biovolume are measurements of phytoplankton standing crops. During 2006, the lowest density (511 units/mL) and biovolume (143 mm3 /m 3 ) occurred at Location 2.0 in February (Table 3-2, Figure 3-1). The maximum density (4,345 units/mL) and biovolume (6,939 mm3 /m 3 ) were observed at Location 5.0 in November. Standing crop values during February, May, and August 2006 were lower than those of 2005, while values from November 2006 were much higher than in November of the previous year (Duke Energy 2006). Phytoplankton densities during 2006 never exceeded the NC guideline for algae blooms of 10,000 units/mL; however, biovolumes at all but Location 11.0 in November exceeded the guideline of 5,000 mm 3 /m 3 for biovolumes (NCDEHNR 1991). Densities and biovolumes in excess of NC guidelines were recorded in 1987, 1989, 1997, 1998, 2000, and 2003 (Duke Power Company 1988, 1990; Duke Power 1998, 1999, 2001, 2004). During most sampling periods phytoplankton densities and biovolumes demonstrated a spatial trend similar to that of chlorophyll; that is, lower values at down-lake locations verses up-lake locations (Table 3-2, Figure 3-1).

Seston Seston dry weights represent a combination of algal matter and other organic and inorganic material. Dry weights during 2006 were generally higher than those of 2005. As was observed in algal standing crops, a general pattern of increasing values from down-lake to up-lake was observed during most quarters to varying extents (Table 3-3 and Figure 3-1). From 3-4

1995 through 1997 seston dry weights had been increasing (Duke Power 1998). Values from 1998 through 2001 represented a reversal of this trend, and were in the low range at most locations during 1999 through 2001 (Duke Power 2002). Low dry weights during these years were likely a result of prolonged drought conditions (Figure 2-2a). Since 2002, dry weights have gradually increased throughout the lake.

Seston ash-free dry weights represent organic material and may reflect trends, of chlorophyll

a. This relationship held true during all but November 2006 (Tables 3-2 and 3-3). Even in November the relationship was valid at most locations, but was completely opposite at Location 69.0. This would indicate that the principle component of ash-free dry weights from Location 69.0 in November were non-algal organic materials.

The proportions of organic material among solids during 2006 were most often lower than in 2005. From 1996 through 2001 there was a trend of decreasing ash-free dry weight to dry weight ratios, followed by a trend of increasing ratios through 2005, indicating higher organic contributions to total solids over the last four years (Duke Power Company 1997; Duke Power 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, Duke Energy 2006). That trend was reversed in 2006.

Secchi Depths Secchi depth is a measure of light penetration. Secchi depths were often the inverse of suspended sediment (seston dry weight), with the shallowest depths at Locations 13.0 through 69.0 and deepest from Locations 9.5 through 2.0 down-lake. Depths ranged from 1.15 m at Location 69.0 in August, to 2.65 m at Location 2.0, also in August (Table 3-1).

The lake-wide mean Secchi depth during 2006 was slightly higher than in 2005 and was within historical ranges for the years since measurements were first reported in 1992. The deepest lake-wide mean Secchi depth was recorded for 1999 (Duke Energy 2006).

Community Composition One indication of "balanced indigenous populations" in a reservoir is the diversity, or number of taxa observed over time. Lake Norman typically supports a rich community of phytoplankton species. This was certainly true in 2006. Ten classes comprising 91 genera and 243 species, varieties, and forms of phytoplankton were identified in samples collected during 2006, as compared to 100 genera and 242 lower taxa identified in 2005 (Table 3-4).

3-5

The 2006 total represented the highest number of species, varieties, and forms recorded in any year since monitoring began in 1987 (Duke Energy 2006). Seventeen taxa previously unrecorded during historical monitoring of Lake Norman were identified during 2006.

Species Composition and Seasonal Succession The phytoplankton community in Lake Norman varies both seasonally and spatially.

Additionally, considerable variation may occur between years for the same months sampled.

During February 2006, cryptophytes (Cryptophyceae) dominated densities at all locations (Table 3-5, Figures 3-5 through 3-9). During most previous years, cryptophytes and occasionally diatoms dominated February phytoplankton samples in Lake Norman. The most abundant cryptophyte during February 2006 was the small flagellate Rhodomonas minuta. R.

minuta has been one of the most common and abundant forms observed in Lake Norman samples since monitoring began in 1987. Cryptophytes are characterized as light limited, often found deeper in the water column or near surface under low light conditions, which are common during winter (Lee 1989).

In May, diatoms (Bacillariophyceae) were dominant at all locations (Table 3-5, Figures 3-5 through 3-9). The most abundant diatom at all but Location 15.9 was the centrate, Cyclotella stelligera. At Location 15.9, the pinnate, Fragillariacrotonensis was the most important diatom. Diatoms have typically been the predominant forms in May samples of previous years; however, cryptophytes dominated May samples in 1988, and were co-dominants with diatoms in May 1990, 1992, 1993, and 1994 (Duke Power Company 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997; Duke Power 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, Duke Energy 2006).

During August 2006 green algae (Chlorophyceae) dominated densities at all locations (Figures 3-5 through 3-9). The most abundant green alga was the small desmid, Cosmarium asphearosporum var. strigosum (Table 3-7). During August periods of the Lake Norman study prior to 1999, green algae, with blue-green algae (Myxophyceae) as occasional dominants or co-dominants, were the primary constituents of summer phytoplankton assemblages, and the predominant green alga was also C. asphearosporum var. strigosum (Duke Power Company 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997; Duke Power 1998, 1999). During August periods of 1999 through 2001, Lake Norman phytoplankton assemblages were dominated by diatoms, primarily the small pinnate, Anomoeoneis vitrea 3-6

(Duke Power 2000, 2001, 2002). A. vitrea has been described as typically periphytic and widely distributed in freshwater habitats and was identified as a major contributor to periphyton communities on natural substrates during studies conducted from 1974 through 1977 (Derwort 1982). The possible causes of this significant shift in summer taxonomic composition were discussed in earlier reports and included deeper light penetration (the three deepest lake-wide secchi depths were recorded from 1999 through 2001), extended periods of low water due to drawdown, and shifts in nutrient inputs and concentrations (Duke Power 2000, 2001, 2002). Whatever the cause, the phenomenon was lake-wide and not localized near MNS or Marshall Steam Station (MSS); therefore, it was most likely due to a combination of environmental factors, and not station operations. Since 2002, taxonomic composition has shifted back to green algae predominance (Duke Power 2003, 2004, 2005, Energy 2006).

During November 2006, densities at all locations were again dominated by diatoms and the most abundant species at all locations was the pinnate diatom, Tabellariafenestrata(Table 3-5, Figures 3-5 through 3-9). This diatom has been one of the most common and abundant forms found in Lake Norman throughout the Lake Norman Maintenance Monitoring program.

Blue-green algae, which are often implicated in nuisance blooms, were never abundant in 2006 samples. Their overall contribution to phytoplankton densities was lower than in 2005, and densities of blue-greens never exceeded 4% of totals (Duke Energy 2006). Prior to 1991, blue-green algae were often dominant at up-lake locations during the summer (Duke Power Company 1988, 1989, 1990, 1991, 1992).

FUTURE STUDIES No changes are planned for the phytoplankton portion of the Lake Norman Maintenance Monitoring Program.

SUMMARY

Lake Norman continues to be classified as oligo-mesotrophic based on long-term, annual mean chlorophyll concentrations. Chlorophyll concentrations during 2006 were most often 3-7

within historical ranges, however, several record low chlorophyll concentrations were recorded in February, while a few record high concentrations were recorded in November.

Lake-wide mean chlorophyll increased from February through May and August to the annual maximum in November. Some spatial variability was observed in 2006, however, maximum chlorophyll concentrations were most often observed up-lake at Locations 15.9 and 69.0, while minimum chlorophyll concentrations were most often recorded from down-lake at Location 2.0. The highest chlorophyll value recorded in 2006, 15.05 jig/L, was well below the NC State Water Quality standard of 40 .tg/L.

Phytoplankton densities and biovolumes during 2006 were generally lower than in 2005.

Phytoplankton densities during 2006 never exceeded the NC guidelines for algae blooms; however, biovolumes at most locations in November were in excess of the state guideline.

Standing crop values in excess of bloom guidelines have been recorded during six previous years of the program. As in past years, higher standing crops were usually observed at up-lake locations, while comparatively low values were noted down-lake.

Seston dry and ash-free weights were more often higher in 2006 than in 2005 and down-lake to up-lake differences were apparent during most quarters. Maximum dry and ash-free weights were most often observed at Location 69.0. Minimum values were always noted at Locations 2.0 through 8.0. The proportions of ash-free dry weights to dry weights in 2006 were lower than those of 2005, indicating a decrease in organic composition among 2006 samples.

Secchi depths reflected suspended solids, with shallow depths related to high dry weights.

The lake-wide mean secchi depth in 2006 was slightly higher than in 2005 and was within historical ranges recorded since 1992.

Diversity or number of taxa, of phytoplankton was similar to 2005 and had the highest number of individual taxa yet recorded. The taxononic composition of phytoplankton communities during 2006 was similar to those of many previous years. Cryptophytes were dominant in February, while diatoms were dominant during May and November. Green algae dominated phytoplankton assemblages during August. Blue-green algae were less abundant during 2006 than during 2005, and their contribution to total densities never exceeded 4 %.

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The most abundant alga, on an annual basis, was the cryptophyte Rhodomonas minuta. The most abundant diatom in May was Cyclotella stelligera, while the most abundant diatom during November was Tabellaria fenestrata. The small desmid, Cosmarium asphearosporumvar. strigosum was dominant in August 2006. All of these taxa have been common and abundant throughout the Lake Norman Maintenance Monitoring Program.

Lake Norman continues to support highly variable and diverse phytoplankton communities.

No obvious short-term or long-term impacts of station operations were observed.

3-9

Table 3-1. Mean chlorophyll a concentrations (jtg/L) in composite samples and Secchi depths (m) observed in Lake Norman in 2006.

Chlorophyll a FEB MAY AUG NOV Location 2.0 1.43 2.19 2.19 8.13 5.0 1.78 2.34 4.65 10.53 8.0 1.59 2.46 2.76 15.05 9.5 1.47 2.94 2.94 11.19 11.0 -1.87 3.92 4.81 8.96 13.0 2.38 5.03 2.26 9.10 15.9 3.14 5.09 5.50 9.13 69.0 3.00 5.13 11.37 2.23 Secchi depths FEB MAY AUG NOV Location 2.0 2.00 2.43 2.65 2.20 5.0 2.10 2.29 2.20 2.10 8.0 2.10 2.32 2.40 2.20 9.5 2.10 2.10 2.46 1.75 11.0 1.82 2.43 2.26 1.61 13.0 1.90 1.86 1.20 1.35 15.9 1.55 1.90 1.75 1.85 69.0 1.41 1.23 1.15 1.43 Annual mean from all Locations: 2006 1.94 Annual mean from all Locations: 2005 1.85 3-10

Table 3-2. Mean phytoplankton densities (units/mL) and biovolumes (mm 3/m 3 ) by location and sample month from samples collected in Lake Norman, NC, during 2006.

Density Locations Month 2.0 5.0 9.5 11.0 15.9 Mean FEB 511 543 527 747 931 652 MAY 699 773 911 1,224 2,604 1,242 AUG 1,520 2,039 1,556 2,254 3,926 2,259 NOV 3,588 4,345 4,315 3,768 3,996 4,002 Biovolume Locations Month 2.0 5.0 9.5 11.0 15.9 Mean FEB 143 172 144 261 485 241 MAY 364 432 520 809, 1,983 822 AUG 864 1,479 1,002 1,833 3,237 1,683 NOV 5,455 6,939 6,743 4,687 5,157 5,796 Table 3-3. Total Total mean seston dry and ash free dry weights (mg/L) from samples collected in Lake Norman, NC during 2006.

Dry weights Locations Month 2.0 5.0 8.0 9.5 11.0 13.0 15.9 69.0. Mean FEB 1.59 1.67 1.45 1.95 2.67 2.69 2.70 16.69 3.93 MAY 1.71 1.46 1.42 1.94 1.85 2.56 2.86 11.51 3.16 AUG 1.31 1.37 1.34 1.38 1.61 3.20 2.67 5.87 2.34 NOV 1.55 1.81 2.20 1.94 1.26 1.65 1.46 1.21 1.64 Ash free dry weights Month FEB 0.55 0.65 0.52 0.68 1.00 0.92 1.05 2.58 0.99 MAY 0.54 0.59 0.70 0.76 0.85 1.25 1.32 1.92 0.99 AUG 0.57 0.63 0.57 0.59 0.76 1.84 1.45 3.16 1.19 NOV 0.72 1.01 1.36 1.05 0.81 1.15 1.09 0.36 0.94 3-11

Table 3-4. Phytoplankton taxa identified in quarterly samples collected in Lake Norman each year from 1991 to 2006.

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 CLASS: CHLOROPHYCEAE AcanthosphaerazachariasiLemm. X X Actidesmium hookeri Reinsch X Actinastrum hantzchii Lagerheim X X X X X Ankistrodesmus braunii (Naegeli) Brunn X X X X X X X X X X X X A. convolutus Corda X A. falcatus (Corda) Ralfs X X X X X X X X X X X X X X X X A.fusiformis Corda sensu Korsch. X X X X A. nannoselene Skuja X A. spiralis (Turner) Lemm. X X X A. spp. Corda X X Arthrodesmus convergens Ehrenberg X X X X X A. incus (Breb.)Hassall X X X X XX X XX A. octocornis Ehrenberg X X X X A. ralfsiiW. West X X X A. subulatus Kutzing. X X X X X X X X X X A. validus v. increassalatusScott & Gron. X A. spp. Ehrenberg X X Asterococcus limneticus G. M. Smith X X X X X X X X X A. superbus (Cienk.) Scherffel X Botryococcus brauniiKutzing X X CarteriafrtzschiiTakeda X X X X X C. globosa Korsch X X X C. spp. Diesing X X X X Characiumambiguum Hermann X C. limneticum Lemmerman X C. spp. Braun 1 Chlamydomonas spp. Ehrenberg X X X X X X X X X X X X X X X X Chlorella vulgaris Beyerink X X X Chlorogonium euchlorum Ehrenberg X X X X X X C. spiraleScherffel & Pascher X X_ X X X Closteriopsislongissima W. & West X X X X X X X X X X X X X X X X Closterium acutum Breb. X C. cornu Ehrenberg X X C. gracile Brebisson X C. incurvum Brebisson X X X X X X X X X X X X X C. parvulum Nageli X C. tumidum Johnson X C. spp. Nitzsch X X Coccomonas orbicularisStein X _X X X X Coelastrum cambricum Archer X X X X X X X X X X X X X X X X C.microporum Nageli X X X X X X X C. reticulatum (Dang.) Sinn. X X C. sphaericumNageli X X X XX X X X X X X C.proboscideum Bohlin X C. spp. Nageli X Cosmarium angulosum v. concin. (Rab) W&W X X X X C. asphaerosporumv. strigosum Nord. X X X X X X X X X X X X X X X X 3-12

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 C. contractum Kirchner X - X X X X "X X X X X X X X X C. moniliforme (Turp.) Ralfs X X X X C. notabile Brebisson X C. phaseolus f. minor Boldt. X X X X X X C. pokornyanum (Grun.) W. & G.S. West X X X C. polygonum (Nag.) Archer X X X X X X X X X X X X C. raciborskiiLagerheim X X X C. regnellii Wille X X XX X X X X X X X X C. regnesi Schmidle X X X X C. subreniforme Nordstedt X X C. subprotumidum Nordst. X C. tenue Archer X X X X XX X X X X X X C. tinctum Ralfs X X X X X X X X X X X X X X C. tinctum v. subretusum Messik. X C. tinctum v. tumidum Borge. X X X X X X X X X C. trilobatum v. depressum Printz X C. tumidum Borge X C. spp. Corda X X X X Crucigeniaapiculata(Lemm.) Schmidl X X X C crucifera (Wolle) Collins X X X X X X X X X X X X X C. fenestrata Schmidle X _ X X X X X C. irregularisWille X X X X X X X X X X X C. rectangularis(A. Braun) Gay X X C. tetrapedia(Kirch.)West&West X X X X X X X X X X X X X X X X DictyospaeriumehrenbergianumNageli X X X X X X D. pulchellum Wood X X X X X X X XXX X X X X X X Dimorphococcus spp. Braunl Elakatothrixgelatinosa Wille X X X X X X X X X X X X X X X X Errerellabornheimiensis Conrad X X X X Euastrum ansatum v. dideltiforme Ducel. X E. banal (Turp.) Ehrenberg X E. denticulatum (Kirch.) Gay X X X X X X X X X X X X E. elegans Kutzing X E. spp. Ehrenberg X X Eudorinaelegans Ehrenberg X X X X X Franceiadroescheri (Lemm.) G. M. Sm. X X X X X X X X X X X X F. ovalis (France) Lemm. X X X X X X X X X X F. tuberculataG. M. Smith X Gloeocystis botryoides (Kutz.) Nageli X I X X X G. gigasKutzing. X X X X X X X X X X X G. major Gemeck ex. Lemmermann I X X G. planktonica (West & West) Lemm. X X X X X X X X X X X X X X X X G. vesciculosa Naegeli X X X X X X G. spp. Nageli X X X X GolenkiniapaucispinaWest & West X X X X X G. radiata Chodat X X X X X X X X X X X X X X X X Gonium pectoraleMueller . X X X X G. sociale (Duj.) Warming X X X X X X X X Kirchneriella contorta(Schmidle) Bohlin X X X X I X X X X K. elongata G.M. Smith I _II_ II _X I I X 3-13

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 K. lunaris (Kirch.) Mobius X XX K. lunaris v. dianae Bohlin X X X X X X X K. lunaris v. irregularisG.M. Smith X X K. obesa W. West X X X X X K. subsolitariaG. S. West X X X X X X X X X X X K. spp. Schmidle X X X X X X Lagerheimiaciliata (Lagerheim) Chodat X X L. citriformis (Snow) G. M. Smith X X X L. longiseta (Lemmermann) Printz X X X X L. quadriseta(Lemm.) G. M. Smith X X L. subsala Lemmerman X X X X X X X X X X X X X Mesostigma viride Lauterbome X X X X X X X X X X X Micractinium pusillum Fresen. X X X X X X X x X. X X X X X X X Monoraphidium contortum Thuret X X X X M pusillum Printz X X X X Mougeitia elegantulaWhittrock X X X X X X X X X X X X M spp. Agardh X X X Ixxx Nephrocytium agardhianumNageli X X X X X X N. ecdysiscepanum W. West X N. limneticum (G.M. Smith) G.M. Smith X X X X N. obesum West & West X Oocystis boriiSnow X X X X X X X

0. ellyptica W. West X X X X

0. lacustris Chodat X X X

0. parva West & West X X X X X X X X X X X X

0. pusilla Hansgirg X X X X X X X X X X X X X X

0. pyriformis Prescott X X

0. solitariaWittrock X X

0. submarinaLagerheim X O. spp. Nagelil PandorinacharkowiensisKprshikov X X P. morum Bory X X X XX Pediastrumbiradiatum Meyen X X P. duplexMeyen X X XX X XX X X XX X P. duplex v. clatheatum (A. Braun) Lag. X P. duplex v.-gracillimum West and West X X X X X X X P. tetras v. tetroadon(Corda) Rabenhorst X X X X X X X X X X X X X X X X P. spp. Meyen X Planktosphaeriagelatinosa G. M. Smith X X X X Quadrigulaclosterioides (Bohlin) Printz X X.X X X X X X Q. lacustris (Chodat) G. M. Smith X X X X X Scenedesmus abundans (Kirchner) Chodat X X X S. abundans v. asymetrica (Schr.) G. Sm. X X X X X X X X X X X S. abundans v. brevicaudaG. M. Smith X X X S. acuminatus (Lagerheim) Chodat X X X X X X X X X X X X X X S. armatus v. bicaudatus (Gug.-Pr..)Chod X X X X X X X X X X X X X X X X S.bijuga (Turp.) Lagerheim X X X X X X X X X X X X X X S. bijuga v. alterans(Reinsch) Hansg. X X S. brasiliensisBohlin _X X X X X X X X X X X X 3-14

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 S. denticulatus Lagerheim X X X X X X X X X X X X X X X S. denticulatus v. recurvatus Schumacher X X X X S. dimorphus (Turp.) Kutzing X X X X X X X X X X X X S. incrassulatusG. M. Smithl S. opoliensis P. Richter X S. parisiensisChodat X X S. quadricauda(Turp.) Brebisson X X X X X X X X X X X X X X X X S. smithii Teiling X X X X X S. serratus(Corda) Bohlin X S. spp. Meyen X X XX Schizochlamys compacta Prescott X X X X X X S.g elatinosaA. Braun X X X X X Schoederia setigera (Schroed.) Lemm. X X Selenastrum bibraianumReinsch X S. gracile Reinsch X X X X S. minutum (Nageli) Collins X X X X 'X X X X X X X X X X X X S. westii G. M. Smith X X X X X X X X X X Sorastrum americanum (Bohlin) Schm. X X SphaerocystisschoeteriChodat X X X X X X X X X Sphaerozosmagranulatum Roy & B1.1 Stauastrum americanum (W&W) G. Sm. X X X X X X X X X X X X S. apiculatum Brebisson X X X X X X X X X.X S. brachiatum Ralfs X X X X X X X X S. brevispinum Brebisson X S. chaetocerus(Schoed.) G. M. Smith X X X S. capitulum Brebisson X S. curvatum W. West X XX X X X X X X X X X X X X X S. cuspidatum Brebisson X X X X X X X X X X S. dejectum Brebisson X X X X X S. dickeii v. maximum West & West I - X S. dickeii v. rhomboidium W.& G.S. West X S. gladiosum Turner X S. leptocladum Nordstedt X S. leptocladum v. sinuatum Wolle X S. manfeldtii v.fluminense Schumacher X X X X X X X X X X X S. megacanthum Lundell X X X X X X S. ophiura v. cambricum (Lund) W. & W. X X S. orbiculareRalfs X X S. paradoxum Meyen X X X X X X X X X S. paradoxum v. cingulum W. & W. X X X S. paradoxum v. parvum W. West X X X X X X S. pentacerum (Wolle) G. M. Smith X X X S. subcruciatum Cook & Wille X X X X X X X X X X S. tetracerum Ralfs X X X X X X X X X X X X X X X X S. turgescens de Not. X S. vestitum Ralfs X X S. spp. Meyen X X X Stichococcus scopulinus Hazen X Stigeoclonium spp. Kutzing j X 3-15

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Tetraedronarthrodesmifonne(W.) Wol. X X X X T bifurcatum v. minor Prescott X T. caudatum (Corda) Hansgirg X X X X X X X X X X X X X T. limneticum Borge X T. lobulatum (Naegeli) Hansgirg X T. lobulatum v. crassum Prescott X X T. minmum(Braun) Hansgirg _ X X X X X X X X X X X X T. muticum (Braun) Hansgirg X X X X X X X T obesum (W & W) Wille ex Brunnthaler X T. pentaedricum West & West X X X T. planktonicum G. M. Smith X X X X X X X T regulareKutzing X X X X X T regulare v. bifurcatum Wille X T. regulare v. incus Telling X X T trigonum (Nageli) Hansgirg X X X X X X X X X X X X T trigonum v. gracile (Reinsch) DeToni X X X X X T. spp. Kutzing X I Tetrallantos lagerheimiiTeiling X X X Tetrasporalamellose Prescott X T. spp. Link X X Tetrastrum heteracanthum (Nor.) Chod. X X X T. staurogeniforme (Schroeder) Lemm. X Treubaria setigerum (Archer) G. M. Sm. X X X X X X X X X X X X X X X X Westella botryoides (W. & W.) Wilde. X X X X X W. linearisG. M. Smith X X X X X X Xanthidium antilopariumv.floridense Scott & Gron. X X critatatum v. uncinatum Breb. X X X X X spp. Ehrenberg X X CLASS: BACILLARIOPHYCEAE Achnanthes lanceolataBrebisson X X A. microcephalaKutzing X X X X X XX X X X X X, A. spp. Bory X X X X X X Amphiprora ornate Bailey X Amphora ovalis Kutzing X Anomoeoneis vitrea (Grunow) Ross X X X X X X X X X X X X A. spp. Pfitzer X AsterionellaformosaHassall X X X X X X X X X X X X X X X Attheya zachariasiJ. Brun X X X X X X X X X X X X X X X Cocconeis placentula Ehrenberg X X X C. spp. Ehrenberg X Cyclotella comta (Ehrenberg) Kutzing X X X X X X X X X X X X X C. glomerata Bachmann X X X X X X X X X C. meneghiniana Kutzing X X X X X X X _ X X X X X C. pseudostelligeraHustedtl C. stelligeraCleve & Grunow X X X X X X X X X X X X X X X X C. spp. Kutzing 1 Cymbella affinis Kutzing X X 3-16

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 C. gracilis(Rabenhorst) Cleve X X C. minuta (Bliesch & Rabn.) Reim. X X X X X X X X X X X C. tumida (Brebison) van Huerck X C. turgida (Gregory) Clevel C. spp. Agardh X Denticula elegans Kutzing X X D. thermalis Kutzing X X X Diploneis ellyptica (Kutzing) Cleve X D. ovalis (Hilse) Cleve X D. puella (Schum.) Cleve X D. spp. Ehrenbergl Eunotia flexuosa v. eurycephala Grun. X E. zasuminensis(Cab.)Koerner X X X X X X X X X X X X X X X FragilariacrotonensisKitton X X X X X X X X X X X X X X X X F. construens (Ehrenberg) Grunow X Frustuliarhomboides (Ehr.) de Tonil F. rhomboides v. saxonica (Rabh.) de T. X Gomphonema angustatum (Kutz.) Rabh. X G. parvulum Kutz. X X X G. spp. Agardh X X Melosira ambigua (Grunow) O. Muller X X X X X X X X X X X X X X X X M distans (Ehrenberg)Kutzing X X X .X X X X X X X X X X X X X M granulata(Ehrenberg) Ralfs X X X M. ranulatav. angustissima0. Muller X X X X X X X X X X X X X X X X M italica (Ehrenberg) Kutzingl M italica v. tennuissima (Grun.) O.Mull- X M variansAgardh X X X X X M spp. Agardh X X X X X X 7 X X X X X Meridion circulareAgardh X Navicula cryptocephala Kutzing X X X N. exigua (Gregory) 0. Muller X X X N. exigua v. capitataPatrick X N. radiosaKutzing X X N. radiosav. tenella (Breb.) Grun. X X X N. subtilissima Cleve X X X X X N. spp. Bory X X X X X Nitzschia acicularisW. Smith X X X X X X X X X X X X X X N. agnita Hustedt X X X X X X X X X X X X X X X X N. communis Rabenhorst X N. holsatica Hustedt X X XX X X X X X X XX N. kutzingiana Hilse X X N. linearis W. Smith X X N. palea (Kutzing) W. Smith X X X X X X X X X N. sublinearisHustedt X X X X X N. spp. Hassall X X X X X X Pinnulariabiceps Gregory X P. spp. Ehrenberg X X X Rhizosolenia spp. Ehrenberg X X X X X X X X X X X X X X X X 3-17

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 030405 Skeletonema potemos (Weber) Hilse X X X X X X X X X X Stephanodiscus astraea(Her.) Grunow X Stephanodiscus spp. Ehrenberg X X X X X X X X X X X X Surirella angustata Kutz. I X S. linearisv. constricta(Ehr.) GrO. X S.tenuis Mayer X Synedra actinastroidesLemmerman X S. acus Kutzing X X X X X X X X X X S. amphicephalaKutzing X S. delicatissimaLewis _ X X X S. filiformis v. exilis Cleve-Euler X X X X X X X X S. planktonica Ehrenberg X X X X X X X X X X X X X X X X S. rumpens Kutzing X X X XX X X X X X X X S. rumpens v.fragilarioidesGrunowl S. rumpens v. scotica Grunow 1 S. ulna(Nitzsch) Ehrenberg X X X X X X X X X X X X S. spp. Ehrenberg X X X X Tabellariafenestrata(Lyngb) Kutzing X X X X X X X X X X X X X X X X T. flocculosa (Roth.) Kutzing X X X CLASS: CHRYSOPHYCEAE A ulomonas purdyLi Lackey X X X X X X X X X X X X Bicoecapetiolatum (Stien) Pringsheim X X Calycomonaspascheri (Van Goor) Lund X X X CentritractusbelanophorusLemm. X Chromulinanebulosa Pascher X Chromulina spp. Chien. X X X X X Chrysococcus rufescens Klebs X ChrysosphaerellasolitariaLauterb. X X X X X X X X X X X X X X X X Codomonas annulataLackey X X X X X X X X X X Dinobryon bavaricum Imhof X X X X X X X X X X X X X X X X D. cylindricum Irnhof X X X X X X X X Xx D. divergens Imhof X X X X X X X X X X X D. pediforme (Lemm.) Syein. X D. sertulariaEhrenberg X X X X X X X D. spp. Ehrenberg X X X X X X XX X X X X X Domatomococcus cylindricum Lackey X X X Erkinia subaeguicilliataSkuja - X X X X X X X X X X X X X Kephyrion campanuliforme Conrad X K. littorale Lund X X X X X X K. petasatum Conrad X K. rubi-claustriConrad X X X X X K. skujae Ettl1 _ _

K. valkanovii Conrad X X K. spp. Pascher X X X X X X X X X X X X X X X X Mallomonas acaroidesPerty- X X X M. akrokomos (Naumann) Krieger X X X X X X M allantoidesPerty _ _ . X 3-18

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 M. allorgii(Deft.) Conrad -- X - - -

M. alpina Pascher X X _

M caudataConrad X X X X X X X X X X X X M globosa Schiller X X X X .X X X X M producta Iwanoff X X X X M pseudocoronataPrescott X X X X X X X X X X X X X X X X M tonsurataTeiling X X X X X X X X X X X X X XX X M spp. Perty X X X X X Ochromonas granularisDoflein X X X X X X X X X 0.mutabilis Klebs X_ X

0. spp. Wyss X X X X X X X X X X X X X Pseudokephyrionconcinum (Schill.) Sch. X P. schilleri Conrad X X X X X X P. tintinabulum Conrad X P. spp. Pascher X X X RhizochrisispolymorphaNaumann X X X X X X X X R. spp. Pascher X Salpingoecafrequentissima(Zach.) Lem. X X X X X Stelexomonas dichotoma Lackey X X X X X X X X X - X X X X Stokesiella epipyxis Pascher X X X X Synura sphagnicolaKorschikov X S. spinosa Korschikov X X X X X X X X X X X X S. uvella Ehrenberg X X X X X S. spp. Ehrenberg X X X X I Uroglenopsis americana(Caulk.) Lemm. X X X X CLASS: HAPTOPHYCEAE Chrysochromulinaparva Lackey X X X X X X X X X X X X X X X X CLASS: XANTHOPHYCEAE Characiopsisacuta Pascher X X X C. dubia Pascher X X XXXXX X X X X Dichotomococcus curvata Korschikov 1 Ophiocytium capitatum v. longisp. (M) L. X X X X X X Stipitococcus vas Pascher X CLASS: CRYPTOPHYCEAE Cryptomonas erosa Ehrenberg X X X X X X X X X X X X X X X X C. erosa v. reflexa Marsson X X X X X X X X X C. graciliaSkuja X C. marsonii Skuja X X X X X C. obovata Skuja X X X C. ovata Ehrenberg X X XX X X X X X X X X X X X X C. phaseolus Skuja X X X X C. reflexa Skuja X X XX X X X X X X X X X X X X C. spp. Ehrenberg X X X X Rhodomonas minuta Skuja X X X X X X X X X X X X X X X X 3-19

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 CLASS: MYXOPHYCEAE I Agmenellum quadriduplicatumBrebisson X X X X X X X X X X X X X X A. thermale Drouet and Daily X Anabaena catenula (Kutzing) Born. X X A. inaegualis (Kutzing) Born. X A. scheremetievi Elenkin X X X X X A. wisconsinense Prescott X X X X X X X X X X X X A. spp. Bory X X X X X X X X X X Anacystis incerta (Lemm.) Druet & Daily X X X X X X X A. spp. Meneghinil Chroococcus dispersus (Keissl.) Lemm. X X C. giganteousW. West X

". limneticus Lemmermann X X X X X X X X X C. minor Kutzing X X X X C. turgidus (Kutz.) Lemmermann X X C. spp. Nageli XX X XX XX X XXXXX X XX Coelosphaeriumkuetzingiana Nageli C. neagleanum Unger X DactylococcopsisirregularisHansgirg X X X Xx D. rupestrisHansgirg X D. smithii Chodat and Chodat X X X .X X X X D. spp. Hansgirg X Gomphospaerialacustris Chodat X X X X X Lyngbya contorta Lemmermann X X L. limnetica Lemmermann X X X X L. ochracea (Kutzing) Thuret X X X X L. subtilis W. West X X X L. tenue Agardh X L. spp. Agardh XX X X X X X X X X X X X X X X Merismopedia tenuissima Lemmermann X Microcystis aeruginosaKutzing X X X X X X X X X X X X X Oscillatoriaamoena (Kutz.) Gomont X

0. amphibia Agardh X X X X

0. geminataMeneghini X X X X X X X X X X X X

0. limnetica Lemmermann X X X X X X X X X X X X

0. splendida Greville X X X X

0. subtilissima Kutz. X X X X X X X

0. spp. Vaucher X X X Phormidium angustissimum West & West X X P. spp. Kutzing X X Raphidiopsis curvata Fritsch & Rich X X X X X X X X X X R. mediterraneaSkuja X RhabdodermasigmoideaSchm. & Laut.1 Spirulinasubsala Oersted X Synecococcus lineare (Sch. & Lt.) Kom. X X X X X X X X X X X X CLASS: EUGLENOPHYCEAE Euglena acus Ehrenberg I IXI _ XI Xx 3-20

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 E. deses Ehrenberg X X E. minuta Prescott X X X X E. polymorpha Dangeard X X X X X E. proxima Dangeard X X X X E. spp. Ehrenberg X X X X X X X X X X X Lepocinclus acicularisFrance X Lepocinclus acuta Prescott X L. glabraDrezepolski X L. ovum. (Ehr.)Lemm. X X L. spp. Perty X Phacus cuvicauda Swirenko X P. longicauda (Her.) Dujardin X P. orbicularisHubner X X P. tortus (Lemm.) Skvortzow X P. triguterPlayfair X P. spp. Dujardinl Trachelomonas abrupta(Swir.) Deflandre X T. abrupta v. minor Deflan. X X T acanthostoma(Stk.) Defi. X X X X T. ensifera Daday X T hispida (Perty) Stein X X X X X X XX T lemmermanii v. acuminataDeflandre X T. pulcherrima Playfairl T pulcherrima v. minor Playfair X T. volvocina Ehrenberg X X X X X X T. spp. Ehrenberg X X CLASS: DINOPHYCEAE Ceratiumhirundinella(OFM) Schrank X X X X X X X C. hirundinellav. brachyceras(Day.) Est. X Glenodinium borgei (Lemm.) Schiller X G. gymnodinium Penard X X X X X X

-G. palustre (Lemm.) Schiller1 G. penardiforme (Linde.) Schiller X X X X G. quadridens (Stein) Schiller X X G. spp. (Ehrenberg) Stein X X Gymnodinium aeruginosum Stein X X X X X X G. spp. (Stein) Kofoid & Swezy X X X X X X X X X X X X X X Peridinium aciculiferum Lemmermannl P. cinctum (Muller) Ehrenberg X X P. inconspicuum Lemmermann X X X X X X X X X X X X X X X X P. intermedium Playfair X X X X X X X X X P. limbatum (Stokes) Lemm. X P. pusillum (Lenard) Lemmermann X X X X X X X X X X X X X X X P. umbonatum Stein X X X P. willei Huitfeld-Kass X X X P. wisconsinense Eddy X X X X X X X X X X X X X X X X P. spp. Ehrenberg X X X X ____

3-21

Table 3-4. (Continued).

TAXON 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 CLASS: CHLOROMONADOPHYCEAE Gonyostomum depresseum Lauterbome X X X X X X X X G. semen (Ehrenberg) Diesing G.spp. Diesing _ X 1 = taxa found during 1987-89 only 3-22

Table 3-5. Dominant classes, their most abundant species, and their percent composition (in parenthesis) at Lake Norman locations during each sampling period of 2006.

LOC FEBRUARY MAY 2.0 CRYPTOPHYCEAE (57.6) BACILLARIOPHYCEAE (65.6)

Rhodomonas minuta (54.1) Cyclotella stelligera (17.2) 5.0 CRYPTOPHYCEAE (64.9) BACILLARIOPHYCEAE (63.7)

R. minuta (57.9) C. stelligera (15.5) 9.5 CRYPTOPHYCEAE (54.4) BACILLARIOPHYCEAE (58.2)

R. minuta (49.4) C. stelligera (21.3) 11.0 CRYPTOPHYCEAE (69.7) BACILLARIOPHYCEAE (64.6)

R. minuta (63.8) C. stelligera (15.7) 15.9 CRYPTOPHYCEAE (51.8) BACILLARIOPHYCEAE (74.3)

R. minuta (45.4) Fragillariacrotonensis (35.6)

AUGUST NOVEMBER 2.0 CHLOROPHYCEAE (61.8) BACILLARIOPHYCEAE (79.7)

Cosmarium asphearosporum Tabellaria fenestrata (68.8) variety strigosum (27.7) 5.0 CHLOROPHYCEAE (60.3) BACILLARIOPHYCEAE (87.3)

C. asphear. var. strig. (33.5) T. fenestrata (76.3) 9.5 CHLOROPHYCEAE (61.4) BACILLARIOPHYCEAE (84.4)

C. asphear.var. strig. (29.6) T. fenestrata (74.9) 11.0 CHLOROPHYCEAE (58.8) BACILLARIOPHYCEAE (68.1)

C. asphear. var. strig. (32.0) T. fenestrata (58.2) 15.9 CHLOROPHYCEAE (40.2) BACILLARIOPHYCEAE (70.5)

C. asphear.var. strig. (19.5) T. fenestrata (62.6) 3-23

CHLOROPHYLL a (jig/L) DENSITY (unitsftl-)

16 - ..................................... 5000 14 - ........ .. .........................

...... ...................... 4000 12 -

10 - ............. ................ .

3000 8J ............................... ....

6 ................................ . .. 2000 4 .. ............. . ...... ..... .

.................. 1000 2 -------- - ---------

-- -------------------------- Q-------------

0 I I I I I I i I 0

0*00 ooo~.o~ q q W) 9 N Lt) ~

04. ML 0 Ut i r r CO SESTON DRY WEIGHT (mglL) BIOVOLUME (mm31m3) 8000 18 - ...................................... 7000 16 - .....................................

14 - .................................... . 6000 12 - ..................................... 5000 . ........................ .. .. .. .

10 - ................................... 4000 8- .................................. 3000 6- .................................

2000 . .. . . . .. . . . . . .. . . . .

4- ................................ . ...

2 -...L-j 1000 0 0 q q U, 0

0* 10 N~~~ 0 C) I)

LO 0MO qr i i ~ W LOCATIONS FEB MAY AUG NOV 0-Figure 3-1. Pliytoplankton chlorophyll a, densities, biovolumes, and seston weights at locations in Lake Norman, NC in February, May, August, and November 2006.

j 3-24

1 12 11n 10

,J*

0 0

0 I FEB MAY AUG NOV Figure 3-2. Lake Norman phytoplankton chlorophyll a seasonal means for each year since August 1987.

3-25

MEAN CHLOROPHYLL a (pglL)

FEB MAY 1---2.0 ---- 5.0 I --s-2.0 -u--.0 30 30 ...N..... N.......... ..... ....

25 ...................................

25 ...................... ............

20 20 ..................................

15 . ............... ................... 15 ..................................

10 10 5 5-0 n 87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05 8.0 I s 8.0 30 ................................... 30 - -------------------------- -------

25 ................................... 25 - ..................................

20 20 - ..................................

15 ............ .................. 15 - ..................................

10 ............................. 10 - ------ ...... ................

5 - W-Jý... 5- .. ..... .... .. .......

0 ........................... A.

V 87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05 1,11.0 --- 11.0 --'--13.071 30 ................................... 30 -

25 ----------------------------------- 25 -

20 ................................... 20 -

15 ...... .................... ..... 15 n 10 .... . ................... ..... 10 -

5 0

87 89 91 93 95 97 99 01 03 05 5

0 87 89 91 93 95 97 99 01 03 05 1--*- 15.9 1,15.9 --- 69.0 30 . ............................. ..... 30 T 25 ............................. ..... 25 +-- - - - - - - --

20 . ............................ ------ ...... 20+

15 .................... .... 15+ -

10 ----------------------- - . - - 10

. .. .... ... ..... ............. . 5 5

. .. .. ..... .... ... .. . 0 0

87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05 Figure 3-3. Phytoplankton mean chlorophyll a concentrations by location for samples collected in Lake Norman, NC, from February and May 1988 -2006.

3-26

MEAN CHLOROPHYLL a (pg/L)

AUG NOV

-*--2.0 -u--5.0 -I--2.0--w-5.01 35 "MIXING ZONE ................... 35-MDIXNG ZONE 3 0 ---------------------------------- 30 2 5 -.-.------------------------------ 25 ..................................

2 0 ---------------------------------- 20 15 ---------------------------------- 15-5 10 -

0 . 5-0 87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05

-I -8.0 --- 9.5 1,8.0 35- ................................. 35 ..................................

30 ................................. ..................................

25 ................................. 25 - ..................................

20 ................................. 20 - ..................................

15 -------------------------- 15 - ...............

10 10 -

5S 5 v 0 . . . . . . . . . I i i . . . . . . . .

87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05

--.-- 11.0 -u-13.0 1 -011.0 Mi-1.

35 ................................. 35 30 ................ : ................ 30 25 ................................. 25 20 ................................. 20 15 ................................. 15 10 . .... ... . ...... .. .......... 10 5 5 0 0 87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05 1-,-15.9 -- 6 .

--- 15.9 --- 69.0 35 35 ...................................

30 30 ............... ....................

25 25 ...................................

20 . ,.................................. 20 ...................................

15 15 10 10 5 5 0 0 87 89 91 93 95 97 99 01 03 05 87 89 91 93 95 97 99 01 03 05 Figure 3-4. Phytoplankton mean chlorophyll a concentrations by location for samples collected in Lake Norman, NC, from August and November 1987 - 2006.

3-27

6000 D]CHLOROPHYCEAE 19 BACILLARIOPHYCEAE

.....CHRYSOPHYCEAE [] CRYPTOPHYCEAE ....

5500

..... RMYXOPHYCEAE El DINOPHYCEAE ----

5000 MOTHERS

-- 4500 "E

E 4000 .. . .. .. . .. . .. . .. . .. . .. .. . .. . .. .. .. .. .. . .. . .. . .- .*. . .. . .. . .. . .. . .

3500 ............................................................

3000 2500 2000 LU.

, 1500 1000 --- - -I-- - - - - - - - - - - - - -- - - - ----

500

.0 FEB MAY AUG NOV 7000 6000 E

';- 5000 E

E4000 3000 0,

> 2000 0

1000 0

FEB MAY AUG NOV Figure 3-5. Class composition (mean density and biovoiume) of phytoplankton from euphotic zone samples collected at Location 2.0 in Lake Norman, NC, during 2006.

3-28

r 6000 o CHLOROPHYCEAE 0 BACILLARIOPHYCEAE 5500 UCHRYSOPHYCEAE 9 SCRYPTOPHYCEAE ............

5000 E2MYXOPHYCEAE EIDINOPHYCEAE ------------

MOTHERS ............

E 4500 4000 .........................................................--

3500 3000 2500 ....................................... .. . ......... ....

2000 w 1500 0

1000 500 0

FEB MAY AUG NOV 7000 6000 c-E 5000 EE E4000 D 3000

-J 0

> 2000 0

1000 0

FEB MAY' AUG NOV Figure 3-6. Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 5.0 in Lake Norman, NC during 2006.

3-29

6000 ... .DCHLOROPHYCEAE []BACILLARIOPHYCEAE "

5500 ---- CHRYSOPHYCEAE CRYPTOPHYCEAE ."

5000 ......IMYXOPHYCEAE 0 DINOPHYCEAE .-

• J 4500 OTHERS -

E- 4000 0

"E 3500

"- 3000 2500 Z 2000 1500 1000 500 0

FEB MAY AUG NOV 7000 6000

,; 5000 E

E4000 LU z 3000

-j 0

> 2000 0

1000 0

FEB MAY AUG NOV Figure 3-7. Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 9.5 in Lake Norman, NC during 2006.

3-30

6000*-

5500-5000-4500-E 4000-

...MOTHERS DOHLOROP MCHRYSOPHYCEAE 1MYXOPHYCEAE SBAOLL S]CRYPTOPHYCEAE 13 DINOPHYCEAE iii E 3500- ...................................................... .....

3000-2500-U)

Z 2000. ......................

1500- ..... .... .... ....

1000-500-0 FEB MAY AUG NOV 7000-6000.

"E c;-* 5000-E 4000-w 3000-0

> 2000 0

1000.

0.

FEB MAY AUG NOV Figure 3-8. Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 11.0 in Lake Norman, NC during 2006.

3-31

8000 DCHLOROPHYCEAE 0 BACILLARIOPHYCEAE IIICHRYSOPHYCEAE 15CRYPTOPHYCEAE 7000 0 MYXOPHYCEAE 13DINOPHYCEAE 6000 MOTHERS (A

5000 ------------------------------------------------------------------

4000 ------------------------------------------------------ .....

0, 3000 z

w 2000 --------------------- ......... ......... -----

0 1000o ..................... ......... .........

0-FEB MAY AUG NOV 7000 6000 S........................................................ -..........

E; 5000 .......................................................- - -

E E 4000 IU .......................................  :*'...........

D 3000

-J 0

> 2000 0

1000 0

FEB MAY AUG NOV Figure 3-9. Class composition (mean density and biovolume) of phytoplankton from euphotic zone samples collected at Location 15.9 in Lake Norman, NC during 2006.

3-32

CHAPTER 4 ZOOPLANKTON INTRODUCTION The objectives of the Lake Norman Maintenance Monitoring Program for zooplankton are to:

1. Describe and characterize quarterly patterns of zooplankton standing crops at selected locations on Lake Norman and

2. compare and evaluate, where possible, zooplankton data collected during 2006 with historical data collected during the period 1987 - 2005.

Previous studies of Lake Norman zooplankton populations, using monthly data, demonstrated a bimodal seasonal distribution with highest values generally occurring in the spring, and a less pronounced fall peak. Considerable spatial and year-to-year variability has been observed in zooplankton abundance in Lake Norman (Duke Power Company 1976, 1985; Hamme 1982; Menhinick and Jensen 1974). Since quarterly sampling was initiated in August 1987, distinct bimodal seasonal distribution has been less apparent due to the lack of transitional data between quarters.

METHODS AND MATERIALS Duplicate 10 m to surface, and bottom to surface net tows, were taken at Locations 2.0, 5.0, 9.5, 11.0, and 15.9 in Lake Norman (Figure 2-1) during each season: winter (February),

spring (May), summer (August), and fall (October) 2006. For discussion purposes the 10 m to surface tow samples are cal!ed "epilimnetic" samples and the bottom to surface net tow samples are called "whole-column" samples. Locations 2.0 and 5.0 are defined as the "Mixing Zone" and Locations 9.5, 11.0 and 15.9 are defined as "Background locations".

Field and laboratory methods for zooplankton standing crop analysis were the same as those reported in Hamme (1982). Zooplankton standing crop data from 2006 were compared with corresponding data from quarterly monitoring begun in August 1987.

4-1

RESULTS AND DISCUSSION Total Abundance Highest epilimnetic zooplankton densities at Lake Norman locations have predominantly been observed in the spring, with winter peaks observed about 25% of the time, and peaks observed only occasionally in the summer and fall (Duke Power 2006). Contrary to this trend, maximum epilimnetic densities were observed in the fall at all but Locations 11.0 and 2.0, which demonstrated yearly maxima in the spring (Table 4-1, Figures 4-1 and 4-2). The lowest epilimnetic densities occurred in the summer at Locations 2.0, 11.0 and 15.9, and in the winter at Locations 5.0 and 9.5. Epilimnetic zooplankton densities ranged from a low of 21,666/M 3 at Location 5.0 in the winter, to a high of 328,755/m 3 at Location 15.9 in the fall.

Maximum densities in all whole-column samples were observed in the fall (Table 4-1 and Figure 4-1). Minimum whole-column densities were observed in the winter at Locations 5.0, and 9.5, in the spring at Location 2.0, and in the summer at Locations 11.0 and 15.9. Whole-column densities ranged from a low o'f 17,418/M 3 at Location 5.0 in the winter, to 244,209/mi3 at Location 15.9 in the fall. This trend was somewhat similar to that observed for phytoplankton, particularly with annual fall peaks (Chapter 3).

Consistent with historical data, total zooplankton densities were most often higher in epilimnetic samples than in whole-column samples during 2006 (Duke Energy 2006). This is related to the ability of zooplankton to orient vertically in the water column in response to physical and chemical gradients and the distribution of food sources, primarily phytoplankton, which are generally most abundant in the euphotic zone (Hutchinson 1967).

Since epilimnetic zooplankton communities are far more representative of overall seasonal and temporal trends, most of the following discussion will focus primarily on zooplankton communities in this area of the water column.

Although spatial distribution varied among locations from season to season, a general pattern of lower average densities from the Mixing Zone as compared to Background locations was observed during 2006 (Table 4-1, Figures 4-1 and 4-2). Location 15.9, the uppermost Background location, had higher epilimnetic densities than Mixing Zone locations during all sampling periods (Table 4-1). This spatial trend was similar to that of the phytoplankton (Chapter 3). In most previous years of the program, Background locations had higher mean densities than Mixing Zone locations (Figure 4-3 and Duke Energy 2006).

4-2

Historically, both seasonal and spatial variability of epilimnetic zooplankton densities have been much higher among Background locations than among Mixing Zone locations. The uppermost location, 15.9, showed the greatest range of densities during 2006 (Table 4-1, Figures 4-3 through 4-6). Apparently, epilimnetic zooplankton communities are more greatly influenced by environmental conditions at the up-lake locations than at the down-lake locations. Location 15.9 represents the transition zone between river and reservoir where populations would be expected to fluctuate due to the dynamic nature of this region of Lake Norman. At the locations nearest the dam (Locations 2.0 and 5.0), seasonal variations are dampened and the overall production would be lower due to the relative stability of this area (Thornton, et al. 1990). Additionally, the effects of MNS once-through cooling could cause somewhat lower production at these locations. A similar trend was observed in the phytoplankton communities (Chapter 3).

Epilimnetic zooplankton densities during 2006 were most often within historical ranges (Figures 4-3 through 4-6). The exceptions were noted during the fall, when all but Location 15.9 demonstrated long-term historical maxima for this time of year (Figure 4-6).

The highest winter densities recorded from Locations 2.0 and 11.0 occurred in 1996, while winter maxima at Locations 9.5 and 15.9 were recorded for 1995 and 1992, respectively (Figure 4-3). The winter maximum from Location 5.0 occurred in 2004. Long-term maximum densities for spring were observed at Locations 2.0 and 5.0 in 2005, while the highest spring values from Locations 11.0 and 15.9 occurred in 2002. The highest spring peak at Location 9.5 was observed in 2005 (Figure 4-4). Long-term summer maxima occurred in 1988 at all but Location 15.9, which had its highest summer value in 2003 (Figure 4-5). Long-term maxima for the fall occurred at all but Location 15.9 in 2006, while the long-term maximum at Location 15.9 was recorded in 1999 (Figure 4-6).

From 1990 - 2003, the densities at Mixing Zone locations in the spring, summer, and fall demonstrated moderate degrees of year-to-year variability, and the long-term trend at Mixing Zone locations in the spring had been a gradual increase over the last 15 years with long-term peaks recorded in 2005. During the spring of 2006, zooplankton densities in the Mixing Zone declined sharply as compared to 2005, and were well within earlier historical ranges.

Year-to-year fluctuations of densities in the Mixing Zone during the winter have occasionally been quite striking, particularly between 1991 and 1997. The Background locations continue to exhibit considerable year-to-year variability in all seasons (Figures 4-3 through 4-6).

4-3

Community Comvosition One hundred and twenty-one zooplankton taxa have been identified since the Lake Norman Maintenance Monitoring Program began in August 1987 (Table 4-2). Forty-four taxa were identified during both 2006 and 2005 (Duke Energy 2006). One previously unreported taxon, the rotifer Monommata, was identified in 2006.

During 2005, copepods were the least abundant forms, and were dominant in only two samples (Duke Energy 2006). In 2006, copepods were dominant in eight samples; one in the winter and seven in the summer (Table 4-1). Cladocerans, most often the least abundant forms in Lake Norman, were dominant in three epilimnetic samples (Locations 2.0, 9.5, and 11.0) and two whole-column samples (Locations 9.5 and 11.0) in the winter (Table 4-1).

Rotifers were dominant in nearly 68% of all zooplankton samples collected during 2006.

During most years, microcrustaceans (copepods and cladocerans) dominated Mixing Zone samples, but were, less important among Background locations (Figures 4-7 and 4-8).

Compared to 2005 microcrustaceans decreased slightly in relative abundance in the epilimnion of the Mixing Zone, while they showed a slight increase among whole-column samples at these locations (Figure 4-7). At Background locations microcrustacean relative abundances were lower than in 2005 (Figure 4-8).

Copepoda Copepod populations were consistently dominated by immature forms (primarily nauplii) during 2006, as has always been the case. Adult copepods rarely comprised more than 7% of the total zooplankton density at any location. Tropocyclops was the most important genus in adult populations in both epilimnetic and whole column samples, particularly during summer and fall (Table 4-3). This was also the case in previous years (Duke Energy 2006).

Copepods tended to be somewhat more abundant at Background locations than at Mixing Zone locations during 2006, and their densities peaked at Background locations in the spring and at Mixing Zone locations in the fall (Table 4-1). Historically, maximum copepod densities were most often observed during the spring (Figure 4-9).

4-4

Cladocera Bosmina was the most abundant cladoceran observed in 2006 samples, as has been the case in most previous studies (Duke Energy 2006, Hamme 1982). Bosmina often comprised greater than 5% of the total zooplankton densities in both epilimnetic and whole-column samples, and was the dominant taxon in six samples in the winter (Table 4-3). Bosminopsis was also important among cladocerans in the summer when it dominated cladoceran populations in three samples. Similar patterns of Bosmina-Bosminopsis dominance have been observed in past years (Duke Power 2006).

Long-term seasonal trends of cladoceran densities were variable. During 2006, maximum densities in the Mixing Zone occurred in the summer, while peaks at Background locations were observed in the winter. From 1990 to 1993, peak densities occurred in the winter, while in 1994, 1995, 1997, 2000, 2004, and 2005 maxima were recorded in the spring (Figure 4-10). During 1996, 1999, and 2002, peak cladoceran densities occurred in the spring in the Mixing Zone, and in the summer among Background locations. Maximum cladoceran densities in 1998 occurred in the summer. In 2001, maximum cladoceran densities in the Mixing Zone occurred in the winter, while Background locations showed peaks in the fall.

During 2003, maximum densities at Background locations occurred in the summer, while peaks in the Mixing Zone were observed in the fall. Spatially, cladocerans were well distributed among most locations (Table 4-1, Figure 4-2).

Rotifera Polyarthrawas the most abundant rotifer in 2006 samples (Table 4-3). This taxon dominated rotifer populations in all samples during the fall, it was also the dominant rotifer at Locations 2.0 and 5.0 during the spring, and was the dominant rotifer in the epilimnion at Locations 2.0 and 5.0, and in the whole-column at Locations 5.0 and 11.0 in the summer. Conochilus dominated rotifer populations at Location 15.9 in the spring and summer, and Locations 2.0 (whole- column) and 11.0 (epilimnion) in the summer. Keratella was the dominant rotifer in whole- column samples at Locations 11.0 and 15.9 in the winter and Locations 5.0 and 9.5 in the spring. Synchaeta was the dominant rotifer in epilimnetic samples at all but Location 15.9 in the winter, and was dominant in Whole-column samples at Location 11.0 that same season. All of these taxa have been identified as important constituents of rotifer populations, as well as zooplankton communities, in previous studies (Duke Power 2006, Hamme 1982).

4-5

Long-term tracking of rotifer populations indicated high year-to-year seasonal variability.

Peak densities have most often occurred in the winter and spring, with occasional peaks in the summer and fall (Figure 4-11). During 2006, peak rotifer densities were observed in the fall.

FUTURE STUDIES No changes are planned for the zooplankton portion of the Lake Norman Maintenance Monitoring Program.

SUMMARY

Maximum zooplankton densities most often occurred in the fall of 2006, while minimum zooplankton densities were noted in the winter and spring. As in past years, epilimnetic densities were higher than whole-column densities. Mean zooplankton densities tended to be higher among Background locations than among Mixing Zone locations during 2006. Both seasonal and spatial trends of zooplankton populations were similar to those of the phytoplankton. From around 1997 through 2005, a year-to-year trend of increasing zooplankton densities was observed among Mixing Zone locations in the spring. However, during the spring of 2006, densities at these locations declined sharply. Long-term trends showed much higher year-to-year variability at Background locations than at Mixing Zone locations.

Epilimnetic zooplankton densities were generally within ranges of those observed in previous years. The exceptions were record high densities during the fall at all locations except Location 15.9.

One hundred and twenty-one zooplankton taxa have been recorded from Lake Norman since the Program began in 1987 (44 were identified during 2006). One previously unreported taxon, a rotifer, Monommata, was identified during 2006.

Overall relative abundance of copepods in 2006 increased over 2005, and they were dominant in eight samples, most in the summer. Cladocerans were dominant in five samples during the 4-6

winter, while rotifers were dominant in nearly 68% of all samples. The relative abundance of microcrustaceans decreased slightly in the epilimnion of the Mixing Zone and at Background locations since 2005, but had increased among whole-column samples in the epilimnion since the previous year. Historically, copepods and rotifers have most often shown annual peaks in the spring, while cladocerans continued to demonstrate year-to-year variability.

Copepods were dominated by immature forms with adults rarely accounting for more than 7% of zooplankton densities. The most important adult copepod was Tropocyclops, as was the case in previous years. Bosmina was the predominant cladoceran, as has also been the case in most previous years of the Program. Bosminopsis dominated several cladoceran populations during the summer. The most abundant rotifers observed in 2006, as in many previous years, were Polyarthra,Conochilus, Keratella,and Syncheata.

Lake Norman continues to support a highly diverse and viable zooplankton community.

Other than somewhat lower productivity from MNS induced mixing at Locations 2.0 and 5.0, no impacts of plant operations were observed.

4-7

Table 4-1. Total zooplankton densities (no. X 1000/m 3), densities of major zooplankton taxonomic groups, and percent composition (in parentheses) of major taxa in the epilimnion and whole column net tow samples collected from Lake Norman in February, May, August, and October 2006.

Locations Sample Date Sample Type Taxa 2.0 5.0 9.5 11.0 15.9 2/15/2006 Epilimnion Copepoda 20.4 5.8 20.1, 24.9 39.8 (35.9) (26.9) (36.9) (16.4) (18.4)

Cladocera 22.8 3.0 23.6 74.3 32.4 (40.1) (14.1) (43.4) (48.9) (15.0)

Rotifera 13.6 12.8 10.7 52.6 143.5 (24.0) (59.0) (19.6) (34.7) (66.6)

Total 56.8 21.6 54.4 151.8 215.7 Whole Column 2.0 5.0 9.5 11.0 15.9 Depth= 30 m 21 m 21 m 25 m 21 m Copepoda 13.0 7.3 14.9 19.4 29.9 (25.3) (42.0) (34.0) (18.6) (16.8)

Cladocera 16.5 3.3 19.2 44.3 18.2 (32.1 (19.1) (43.8) (42.6) (10.2)

Rotifera 21.9 6.8 9.8 40.4 129.8 (42.6) (38.9) (22.2) (38.8) (73.0)

Total 51.4 17.4 43.9 104.1 177.9 Locations Sample Date Sample Type Taxa 2.0 5.0 9.5 11.0 15.9 2/15/2006 Epilimnion Copepoda 29.7 17.6 27.1 51.2 47.7 (37.9) (19.2) (24.5) (24.9) (22.7)

Cladocera 11.2 13.7 5.6 16.0 16.3 (14.3) (15.0) (5.0) (7.8) (7.7)

Rotifera 37.6 60.2 78.2 138.2 146.4 (47.8) (65.6) (70.5) (67.3) (69.6)

Total 78.5 91.7* 110.9 205.4 210.4 Whole Column 2.0 5.0 9.5 11.0 15.9 Depth= 30 m 20 m 21 m 25 m 22 m Copepoda 16.0 19.1 17.5 34.0 54.8 (38.6) (31.3) (23.8) (35.6) (37.3)

Cladocera 6.8 8.5 3.4 10.1 10.8 (16.5) (13.9) (4.6) (10.6) (7.3)

Rotifera 18.6 33.5 52.6 51.4 81.4 S(54.8)(44.9) 5 (71.6) (53.8) (55.4)

Total 41.4 61.1 73.5 95.5 147.0 4-8

Table 4-1. (Continued).

Locations Sample Date Sample Type Taxa 2.0 5.0 9.5 11.0 15.9 8/29/2006 Epilimnion Copepoda 24.4 15.4 28.0 27.4 41.8 (47.2) (40.6) (42.1) (28.0) (38.6)

Cladocera 16.4 11.9 18.1 18.5 15.6 (31.9) (31.5) (27.3) (18.9) (14.4)

Rotifera 10.8 10.6 20.3 52.0 50.7 (20.9) (27.9) (30.6) (53.1) (46.8)

Total 51.6 37.9 66.4 97.9 108.3*

Whole Column 2.0 5.0 9.5 11.0 15.9 Depth= 30 m 21 m 21 m 25 m 21 m Copepoda 50.4 16.1 32.7 22.2 39.8 (60.3) (50.5) (49.8) (32.2) (42.0)

Cladocera 22.6 9.6 21.2 13.8 14.9 (27.1) (30.0) (32.3) (20.0) (15.8)

Rotifera 10.5 6.3 11.8 33.0 38.7 (12.6) (19.5) .(17.9) (47.8) (40.8)

Total 83.5 32.0 65.7 69.0 94.7*

Locations Sample Date Sample Type Taxa 2.0 5.0 9.5 11.0 15.9 10/29/2006 Epilimnion Copepoda 25.6 27.0 28.4 37.1 37.0 (33.8) (16.3) (12.6) (19.7) (11.3)

Cladocera 4.3 9.5 4.1 11.2 5.8 (5.7) (5.8) (1.8) (5.9) (1.7)

Rotifera 45.7 128.5 193.0 140.0 285.9 (60.5) (77.9) (85.6) (74.4) (87.0)

Total 75.6 165.0 225.5 188.3 328.7 Whole Column 2.0 5.0 9.5 11.0 15.9 Depth= 30 m 20 m 21 m 25 m 22 m Copepoda 30.0 23.3 17.7 64.5 29.1 (34.8) (21.4) (15.9) (28.3) (11.9)

Cladocera 9.3 8.5 1.8 14.4 4.5 (7 8(10.8)

) (1.7) (6.3) (1.9)

Rotifera 46.9 77.3 91.4 149.1 210.6 (54.4) (70.8) (82.4) (65.4) (86.2)

Total 86.2 109.1 110.9 228.0 244.2

• = Chaoborus(Insecta) observed in epilimnetic samples from Location 5.0 in May (214/M3 0.21%) and Location 15.9 in August (158/M 3, 0.15%), and in bottom to surface samples at Location 15.9 in August (1,322/M 3, 1.4%).

4-9

Table 4-2. Zooplankton taxa identified from samples collected quarterly on Lake Norman from 1987 - 2006.

TAXON 87-92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 COPEPODA Cyclops thomasi Forbes X X X X X X X X X X X X X

". vernalis Fischer X

. spp. O. F. Muller X X X X X X X X X X Diaptomus birgei Marsh X X X _

D. mississippiensis Marsh X X X X X X X X X X X X X X X D. pallidus Herick X X X X X X X X D. reighardiMarsh X D. spp. Marsh X X XX X X X X X X X EpishurafluviatilisHerrick X X X X X X X X X X X X Ergasilus spp. X X Eucyclops agilis (Koch) X Mesocyclops edax (S. A. Forbes) X X X X X X X X X X X X X X M spp. Sars X X X X X X X X X Paracyclopslimbricatus v. poppei I__ X Tropocyclopsprasinus(Fischer) X X X X X X X X X X X X X T spp. (Fischer) X X X X X X X X X X CLADOCERA Alona spp.Baird X X Alonella spp. (Birge) X X Bosmina longirostris(0. F. M.) X X X X X X X X X X X X B. spp. Baird X X X X X X X X X X Bosminopsis dietersiRichard X X X X X X X X X X X X X X X Ceriodaphnialacustris Birge X X X X X X X X X X C. spp. Dana X X XX X X X X X X X X Chydorus spp. Leach X X X X X X X X X X X Daphnia ambigua Scourfield X X X X X X X X D. catawba Coker X X X D. galeataSars X D. laevis Birge X X D. longiremis Sars X X X X X X D. lumholzi Sars X X X X X X X X X D. mendotae (Sars) Birge X X X X X D. parvula Fordyce X X XX X X X X X X X X X D. pulex (de Geer) X X D. pulicariaSars X X D. retrocurva Forbes X X X X X X X X X D. schodleri Sars X D. spp. Mullen X X XX X X X X X X X X X X X Diaphanosoma brachyurum (Lievin) X X X X X X X X X X D. spp. Fischer X X XX X X X X X X X X Disparalonaacutirostris(Birge) X Eubosminaspp. (Baird) X Holopedium amazonicum Stin. X X X X X X X X X X H. gibberum Zaddach X x xX IX I I I I 4-10

Table 4-2. (Continued).

TAXON 87-92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 H. spp. Stingelin X X X X X X X X X X Iiyocryptus sordidus (Lieven) X I. spinifer Herrick X

i. spp. Sars X X X X X X

Latona setifera (O.F. Muller)

Leptodora kindtii (Focke) X X X X X X X X X X X X X X X Leydigia acanthoceroides (Fis.) X L. spp. Freyberg X X X X X X X Moina spp. Baird X Monospilus disparSars X Oxurella spp. (Sars) X Pleuroxus hamulatus Birge X P. spp. Baird X Sida crystallina0. F. Muller X Simocephalus expinosus (Koch) X Simocephalus spp. Schodler X ROTIFERA Anuraeopsisfissa(Gosse) X A. spp. Lauterbome X X X X X X X Asplanchna brightwelli Gosse X X A. priodontaGosse X X X X A. spp. Gosse X X X X X X X X X X X X X X X Brachionuscalyciforus X BrachionuscaudataBar. & Dad. X B. bidentataAnderson X B. havanensis Rousselet X X B. patulus O. F. Muller X X B. spp. Pallas X X X X X Chromogasterovalis (Berg.) X X X X X X C. spp. Lauterborne X X X X X Collotheca balatonicaHarring X X X X X X X X X X C. mutabilis (Hudson) X X X X X X X X X C. spp. Harring X X X X X X X X X X X Colurella spp. Bory de St. Vin. X ConochiloidesdossuariusHud. X X X X X X X X X X C. spp. Hlava X X X X X X X X Conochilus unicornis (Rouss.) X X X X X X X X X X X C. spp. Hlava X X X X X X X x Filiniaspp. Bory de St. Vincent X X X X Gastropus stylifer Imhof X X X X X X G. spp. Imhof X X X X X X X X Hexarthramira Hudson X X X X X X H. spp. Schmada X X X X X X X Kellicottia bostoniensis (Rou.) X X *X X X X X X X X X X X X K. longispina Kellicott X X X X X X X X X X K. spp. Rousselet X X X X X X X X X X X Keratella cochlearis X X X K. taurocephalaMyers X X X X K. spp. Bory de St. Vincent X X X XX X XX X X X XXX 4-11

Table 4-2. (Continued).

TAXON 87-92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Lecane spp. Nitzsch X X X X X X X X X X MacrochaetussubquadratusP. X X M spp. Perty X X X X X X X Monommata spp. x Monostyla stenroosi(Meiss.) X M spp. Ehrenberg X X X X X X Notholca spp. Gosse X X X Platyiaspatulus Harring X Ploeosomahudsonii Brauer X X X X X X X X X X X X X X P. truncatum (Levander) X X X X X X X X X X X X X X P. spp. Herrick X X X X X X X Polyarthraeuryptera (Weir.) X X X X P. major Burckhart I X X X X X X X X P. vulgaris Carlin X I X X X X X X X X X P. spp. Ehrenberg X X X XX X X X X X X X X X X Pompholyx spp. Gosse X Ptyguralibra Meyers X X X X X X X X P. spp. Ehrenberg X X X X X X X X Synchaeta spp. Ehrenberg X X X X X X X X X X X X XXX Trichocercacapucina (Weir.) X X X X X X X T. cylindrica (Imhof) X X XX X X X X X X XX T. longiseta Schrank X X T. multicrinis (Kellicott) - X X X X X X X X T. porcellus (Gosse) X X X X X X X T.pusilla Jennings " X T. similis Lamark X X T. spp. Lamark X X X X X X X X X X X X X X X Trichotriaspp. Bory de St. Vin. X X X Unidentified Bdelloida X X X X X X X Unidentified Philodinidae X Unidentified Rotifera X X X X X X X X X INSECTA Chaoborus spp. Lichtenstein X X- X X X X X X X OSTRACODA (unidentified) X X X 4-12

Table 4-3. Dominant copepod (adults), cladoceran, and rotifer taxa, and their percent composition (in parentheses) of the copepod, cladoceran and rotifer densities by location and sample period in Lake Norman in 2006.

Locations FEBRUARY MAY AUGUST OCTOBER COPEPODA EPILIMNION 2.0 Tropocyclops (1.5) Mesocyclops (7.6)* Tropocyclops (9.7)* Tropocyclops (4.5)*

5.0 No adults Mesocyclops (3.5)* Tropocyclops (9.1)* Tropocyclops (0.7)*

9.5 Tropocyclops (1.2) Tropocyclops (5.1) Tropocyclops (5.7) Tropocyclops (2.9)*

11.0 Mesocyclops (1.9) Tropocyclops (8.0) Tropocyclops (9.7)* Tropocyclops (2.3) 15.9 Mesocyclops (3.7) Tropocyclops (16.6) Tropocyclops (6.5)* Tropocyclops (3.9)*

COPEPODA WHOLE COLUMN 2.0 Tropocyclops (2.5) Tropocyclops (7.6) Tropocyclops (10.0) Tropocyclops (6.3) 5.0 Tropocyclops (3.4) Tropocyclops (7.1) Tropocyclops (7.8) No adults 9.5 Tropocyclops (4.1) Tropocyclops (5.1) Tropocyclops (7.4) Tropocyclops (8.2)

• 11.0 Tropocyclops (5.8) Tropocyclops (7.5) Tropocyclpos (9.8) Tropocyclops (3.8) 15.9 Cyclops (5.1) Tropocyclops (12.8) Mesocyclops (3.8) Tropocyclops (9.3)

CLADOCERA EPILIMNION 2.0 Bosmina (93.2) Bosmina (54.4) Bosmina (70.3) Bosmina (100.0) 5.0 Bosmina (97.4) Bosmina (50.6) Bosminopsis (54.3) Bosmina (100.0) 9.5 Bosmina (94.8) Bosmina (32.1) Bosmina (56.8) Bosmina (100.0) 11.0 -Bosmina (99.0) Bosmina (51.6) Bosmina (48.0) Bosmina (96.2) 15.9 Bosmina (99.0) Bosmina (69.4) Bosminopsis (32.9) Bosmina (75.0)

CLADOCERA WHOLE COLUMN 2.0 Bosmina (94.1) Bosmina (45.1) Bosmina (79.8) Bosmina (92.3) 5.0 Bosmina (89.0) Bosmina (47.9) Bosminopsis (45.0) Bosmina (97.1) 9.5 Bosmina (94.8) Diaphanosoma (52.5) Bosmina (61.5) Bosmina (100.0) 11.0 Bosmina (95.4) Bosmina (30.8) Bosmina (44.8) Bosmina (65.0) 15.9 Bosmina (84.8) Bosmina (80.3) Bosmina (37.8) Bosmina (60.0)

• = Only adults present in samples.

4-13

Table 4-3. (Continued).

Locations FEBRUARY MAY AUGUST OCTOBER ROTIFERA EPILIMNION 2.0 Synchaeta (43.0) Polyarthra(44.0) Polyarthra(52.0) Polyarthra(69.9) 5.0 Synchaeta (57.2) Polyarthra(18.5) Polyarthra(83.0) Polyarthra(84.1) 9.5 Synchaeta (28.1) Keratella (54.3) Trichocerca(41.8) Polyarthra(60.4) 11.0 Synchaeta (40.3) Keratella (62.7) Conochilus (36.7) Polyarthra(59.6) 15.9 Asplanchna (61.0) Conochilus (46.4) Conochilus (37.2) Polyarthra(50.0)

ROTIFERA WHOLE COLUMN 2.0 Conochilus (45.6) Polyarthra(30.8) Conochilus (40.9) Polyarthra(55.9) 5.0 Keratella (31.4) Polyarthra(26.0) Polyarthra(61.6) Polyarthra(70.8) 9.5 Keratella (37.9) Keratella (56.4) Trichocerca(30.3) Polyarthra(48.2) 11.0 Synchaeta (41.1) Keratella (55.8) Polyarthra(34.5) Polyarthra(57.0) 15.9 Asplanchna (76.6) Conochilus (46.6) Cocochilus (66.5) Polyarthra(48.3) 4-14

EPILIMNETIC

-.- FEB ---- MAY e.AUG --- OCT 4 00 CD 50 0

2.0 5.0 9.5 11.0 15.9 Location x

WHOLE COLUMN 3*00 50 0

2.0 5.0 9.5 11.0 15.9 Location Figure 4-1. Total zooplankton density by location for samples collected in Lake Norman in 2006.

4-15

FEBRUARY MAY 250 O COPEPODS [CLADOCERANS.... 250 oCOPEPODS ECLADOCERANS IROTIFERS s ROTIFERS E 2 00 ---~oo------------------ E 200 -- ---- ---------- ...

Co 0D

- 150 C;

............................ 6 150 S

510........................ oo ...

0 0 2.0 5.0 9.5 11.0 15.9 2.0 5.0 9.5 11.0 15.9 Location Location AUGUST OCTOBER 150COPEPODS m CLADOCERANS . ROWIFERS EE 300 ROTIFERS .. 300 mCLADOCERANS O COPEPODS

~250 ...................... 250 . .................. .

o 0_ --

150... ..... ..

o ... ....

100 ' 300 2.0 5.0 9.5 11.0 15.9

-11.0 2.0 5.0 9.5 15.9" Location Location Figure 4-2. Zooplankton community composition by sample period and location for epilimnetic samples collected in Lake Norman in 2006.

4-16

MIXING ZONE LOCATIONS WINTER 225 225 . . ' . . .. . . . . ..............................................................

-.2.0 ................

a5.0 E. 2 0 0 . .................... .............................................................................

CD 175 x

0 15 0 - . .-------- ...... .... ............ .. .... ....... .... ...... ... ..................... ...............

87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year BACKGROUND LOCATIONS 600 E 500 9.5 --s- 11 .0 -.... 15-91 ................................................................

o 400 I-x c 300 200 A

100 a

0 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year Figure 4-3. Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman, NC, in the winter periods of 1988 - 2006.

4-17

MIXING ZONE LOCATIONS SPRING 22 5 - . .........................................................................

.-200 600 50.

250 ... ............................................................................................

88 89 90 91 92 93 94 95 96 97 98 99 00 ---01 -- 02- 03 04 05 06

-- h--- ------ -------

9.5 ---- Year

= 500 BACKGROUND LOCATIONS 60 0 i] -* 5 -= 1 - - -- - -- --- - --- -- - --- -- - --- -- -- -- --

~400 x

,00 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year Figure 4-4. Total, zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the spring periods of 1988 - 2006.

4-18

MIXING ZONE LOCATIONS SUMMER 225 - -: ýi- -- .0 - --5 .07 .. .. .. .. .... ... . ... .. .. ... . .. .. .... ... . .. .. ... .. .. ..*. .. ... ... ... .. ... ... .

200 -

175 150 x 125 6 100 75 U)

C- 50 (D

a 25 -

nV 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year BACKGROUND LOCATIONS 300 -

ME 250 . ............................................................... A--------

CD 200 T-x

150 C

Ž 100

4) 50 a

0 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year Figure 4-5. Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the summer periods of 1987 - 2006.

4-19

MIXING ZONE LOCATIONS FALL 225 2 2 520 .. -.-- . . . --.u--

. . 2.0 . .5.0. ."........................................................................

1-.00.

~-- 75 75 -.-.----------------------------------..................................................... .....

0.

125. . . . .

87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 400 Year 300 BACKGROUND LOCATIONS

.5 10 15.9 C.

0 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year Figure 4-6. Total zooplankton densities by location and year for epilimnetic samples collected in Lake Norman in the fall periods of 1987 - 2006.

4-20

MIXING ZONE: EPILIMNION El COPEPODS R] CLADOCERANS N ROTIFERS 100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

c0 o 04 It (0 00 oO tI* co 00 0) a) 0) 0) a) 0 0 0 0O

0) 0) 0) 0) 0) 0) 0 0 0 0 r- r- r- r- rr 04 04 04 04 MIXING ZONE: WHOLE-COLUMN 100% . ... . . .. . . . . .. . ..

90% . ... . . .. . . . m. i 80%

70%

60% ..-- ... ~ . . . .. . .. ...

50%

-~. . ... .. . . .. . .. . ..

40%

30%

20%

10%

0%

0 04 CDc co 0 04 It (

cO 0) M M 0) c 0 0 0 0

0) 0) 0) 0) 0) 0D 0 0 0 0 YEARS Figure 4-7. Annual percent composition of major zooplankton taxonomic groups from Mixing Zone Locations (Locations 2.0 and 5.0 combined) during 1988 - 2006 (Note: Does not include Location 5.0 in the fall of 2002 or winter samples from 2005).

4-21

BACKGROUND: EPILIMNION C COPEPODS CLADOCERANS 0 ROTIFERS 100% .

90% .

80% .

70% .

60% - . ... . .

50% .

40% -. .. . .. . .

30% .

20% .

10%

0%

00 0) N I- 0D 0 N ' (O

0) M

0) M

0) a0)M 0)M Ma 0

0) 0a o0a 0a IT- ,r- r- . .- ,4N N N N BACKGROUND: WHOLE-COLUMN 100% .

90% .

80% .

70% .

60% .

50%

40% . "

30% " .... .. .

20%/ ..... ..

110%.. . .. . .. .

0%

oo D0 N 't CD oo C0 N VI CD cO 0M 0M 0 0M 0C M 0 0 0 0 0M 0M 0) 0M 0) 0M 0 0 0 0 r r N 04 N 4 YEARS Figure 4-8. Annual percent composition of major zooplankton taxonomic groups from Background Locations (Locations 9.5, 11.0, and 15.9 combined) during 1988 -

2006 (Note: Does not include winter samples from 2005).

4-22

0 0 12 . . . . . . . . . . .. . . . . . . . .. . . .. . . . . . . . . . . . .. . . . . . . . . .. . . .. . . . . . . . . . . . .. . . . . . . . . .. . .. . . . . . . . . . . . .

-- MIXING ZONE -a-BACKGROUND LOCATIONS .

100 .... .

1-0" 0 . .. . .......... I . . .. ...........

I .......... .......... ......... . ........ .........I------............. . . .....................--

0 6 0 - ...-.-- ----.-

-- .-- ............ ... ......r......... ......... ... ....

I-- --- .... ....... ...

1990 1991 I 1992 I 1993 I 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 1 2004 2005 2011 Seasons and Years Figure 4-9.' Copepod densities during each season of each year among epilimnetic samples collected in Lake Norman from 1990 -

2006 (Mixing Zone = mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15.9).

6 -.-- MD(ING ZONE _--BACKGROUND LOCATIONSI ...........................................

............. .......... 7..... :.... ......... ..........  : ......... '".................

50 50 10* . ....... ......

40 .

Seasons and Years Figure 4-10. Cladoceran densities during each season of each year among epilimnetic samples collected in Lake Norman from 1990 -

2006 (Mixing Zone = mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15.9).

3 5 0 ------......... I..........

........... I.......... I............

.. ..... ......... ,.......... :.......... * ......... : ....... -............... ...........I ......... ........... ....... ..........

--- MD(ING ZONE - BACKGROUND LOCATIONS]

300 ...... ... ...... ................. ........ .........

250~~~~~~ . ... .. .. . .. . .. .. . .. . . --------------...

.~~~

250 . . . . . . . . . ...........

i......... ir x.

d 100.................

50 Seasons and Years Figure 4-11. Rotifer densities during each season of each year among epilirnmetic samples collected in Lake Norman from 1990 -

2006 (Mixing Zone = mean of Locations 2.0 and 5.0; Background = mean of Locations 9.5, 11.0, and 15.9).

CHAPTER 5 FISHERIES INTRODUCTION In accordance with the NPDES permit for McGuire Nuclear Station (MNS) and associated requirements from the North Carolina Wildlife Resources Commission (NCWRC),

monitoring of specific fish population parameters in Lake Norman continued during 2006.

The components of this program were:

1. spring electrofishing of littoral fish populations with emphasis on age, growth, size distribution, and condition of spotted bass and largemouth bass;

2. fall electrofishing surveys to assess largemouth and spotted bass young-of-year abundance;

3. summer striped bass mortality surveys;

4. winter striped bass gill net study with the NCWRC with emphasis on age, growth, and condition;

5. fall hydroacoustic and purse seine surveys of pelagic fish abundance and species composition;

6. fall trap-net surveys with the NCWRC for crappies with emphasis on age and growth.

METHODS AND MATERIALS Spring Electrofishing Surveys Spring electrofishing surveys were conducted in late March to early April at three locations:

(1) near Marshall Steam Station (MSS) in Zone 4, (2) a reference (REF) area located between MNS and MSS in Zone 3, and (3) near MNS in Zone 1 (Figure 5-1). The locations sampled in 2006 were identical to historical locations sampled since 1993 and consisted of ten 300-m shoreline transects at each location. Transects included habitats representative of those found in Lake Norman. 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 200 C. All stunned fish were collected and identified to 5-1

species (scientific names of fish collected are listed in Table 5-1). 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. Sagittal otoliths were removed from all bass > 125 mm long (fish < 125 mm were assumed to be age 1 because young-of-year bass are generally not collected in spring samples >20* C) and sectioned for age determination (Devries and Frie 1996). Growth rates were calculated with the mean length for all fish of the same age. Condition using relative weight was calculated for largemouth bass >150 mm long and spotted bass >100 mm long, using the formula Wr =

(W/Ws) x 100, where W = weight of the individual fish (g) and Ws = length-specific mean weight (g) for a fish as predicted by a weight-length equation for that species (Anderson and Neumann 1996).

Fall electrofishing surveys for young-of-year bass Fall electrofishing surveys were conducted in mid-November at the same three locations as spring surveys and consisted of five 300-m shoreline transects at each location. Again, shallow flats where the boat could not access within 3-4 m of the shoreline were excluded.

All stunned bass were collected, identified to species, and individually measured and weighed. A year class "cut off' of 150 mm was determined for all black bass by examining length-frequency data.

Summer striped bass mortality surveys Mortality surveys for striped bass were conducted weekly in July and August to specifically search for dead or dying striped bass in Zones 1-4. All dead striped bass were collected during these surveys and their location noted. Total length was measured prior to disposal.

Striped bass netting survey Striped bass were collected for age, growth, and condition (Wr) determinations in early December by NCWRC and Duke Energy (DE) personnel. Four monofilament nets (76.2 m long x 6.1 m deep), two each containing two 38.1-m panels of 38- and 51-mm square mesh and two each containing 38.1 -m panels of 63- and 76-mm square mesh, were set overnight in areas where striped bass were previously located. Individual total lengths and weights were obtained for all striped bass collected and sagittal otoliths were removed to determine age, 5-2

growth, and condition (Wr) as described previously for largemouth bass. Additionally, all catfish collected were identified to species and enumerated.

Fall hydroacoustics and purse seine The abundance and distribution of pelagic prey fish in Lake Norman were determined using mobile hydroacoustic (Brandt 1996) and purse seine (Hayes et al. 1996) techniques. A mobile hydroacoustic survey of the entire lake was conducted in mid-September to estimate forage fish populations. Hydroacoustic surveys employed multiplexing, side- and down-looking transducers to detect surface-oriented fish and deeper fish (from 2.0 m depth to the bottom), respectively. Both transducers were capable of determining target strength directly by measuring fish position relative to the acoustic axis. Due to its large size and spatial heterogeneity, the lake was divided into six zones (Figure 5-1).

Purse seine samples were also collected in September from the downlake (Zone 1), midlake (Zone 2), and uplake (Zone 5) areas of the reservoir. The purse seine measured 118 x 9 m 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.

Crappie trap-net study The Lake Norman black and white crappie population was sampled using trap nets by the NCWRC and DE in late October as described by Nelson and Dorsey (2005). Individuals were identified to species, measured for total length, weighed, and sagittal otoliths removed for age and growth determinations.

RESULTS AND DISCUSSION Spring Electrofishing Surveys Electrofishing was conducted at water temperatures ranging from 13.4 to 25.1 TC (56.1 to 77.2 'F). Nine hundred twenty four fish (16 species-and two hybrid complexes) weighing 68.8 kg were collected from the MSS area, 1,087 fish (17 species and one hybrid complex) weighing 69.3 kg from the REF area, and 742 fish (13 species and two hybrid complexes) weighing 48.0 kg from the MNS area (Table 5-2). Overall, redbreast sunfish and bluegill 5-3

dominated samples numerically while spotted bass, largemouth bass, and common carp dominated samples gravimetrically.

Total numbers and biomass of fish collected in spring 2006 were highest in the REF area, intermediate in the MSS area, and lowest in the MNS area (Figure 5-2). There is no apparent trend in the number of fish collected within or among areas since 1993; however, overall, biomass has generally been highest in the MSS area, intermediate in the REF area, and lowest in the MNS area. An extreme occurred in the 2003 MSS collection when large numbers of common carp were collected greatly inflating total fish biomass.

Spotted bass, thought to have originated from angler introductions, were first collected in Lake Norman in the 2001 spring electrofishing samples. They have increased in numbers and biomass since 2001 (Figure 5-3) and, in 2006, were most abundant in the MNS area, intermediate in the MSS area, and least abundant in the REF area. Biomass was highest at MNS, intermediate at REF, and lowest at MSS.

In 2006, small spotted bass (< 150 mm) dominated the catch in all areas sampled (Figure 5-4), and their growth rate was generally similar among all areas sampled (Table 5-3). Spotted bass Wr ranged from 69 for fish 150-199 mm long in the MSS area to 90 for fish 350-399 mm long in the REF area (Figure 5-5). Overall, Wr values were highest for REF spotted bass, intermediate at MNS, and lowest at MSS.

In 2006, largemouth bass numbers and biomass decreased at all locations relative to 2005, and values at each location were the lowest recorded since sampling began in 1993 (Figure 5-6). As in most years largemouth bass numbers and biomass were highest at MSS, intermediate at REF, and lowest at MNS.

Since 2000, largemouth bass >300 mm dominated the catch in all three sampling areas (Duke Power 2001, 2002, 2003, 2004, 2005), with largemouth bass < 150 mm low in abundance.

An exception was 2006, where a high abundance of largemouth bass < 150 mm occurred in the MSS area (Figure 5-4). There was no trend in largemouth bass growth among areas in 2006 (Table 5-3); however, largemouth bass mean lengths for ages 2, 3, and 4 were generally higher beginning in 2003 relative to historic data (1974 - 78, 1993, and 1994)(Table 5-4).

While displacement of largemouth bass since the introduction of spotted bass in the lower lake is apparent, the direct effect on largemouth bass recruitment is indeterminate, possibly due to confounding effects of other introductions (e.g., alewives and white perch).

5-4

Largemouth bass Wr was similar for all sizes of fish in all sampled areas in 2006 (Figure 5-5) and similar to that noted in 2003, 2004 (Duke Power 2004, 2005), and 2005 (Duke Energy 2006).

Fall electrofishing surveys for young-of-year bass Fall 2006 electrofishing resulted in the collection of 95 spotted and four largemouth bass young-of-year (< 150 mm) compared to 94 spotted and 20 largemouth bass in 2005.

Additionally three hybrid bass young-of-year were collected in 2006 and four in 2005.

Overall, numbers in both years were highest at MSS, intermediate at MNS, and lowest at REF (Figure 5-7).

Summer striped bass mortality surveys In 2006, a total of six dead striped bass were collected during the July-August surveys (Table 5-5). Since the survey began in 1983, summer mortalities in excess of 25 dead striped bass occurred in three years: 163 in 1983, 43 in 1986, and 2,610 in 2004.

Striped bass netting survey In December 2006, 120 striped bass were collected for age, growth, and Wr determinations (Figure 5-8). Growth of Lake Norman striped bass was slow after age 3, as noted in prior years (Duke Energy 2006; Duke Power 2004, 2005), and, overall, Wr was highest for young fish and decreased with age. The mean Wr for all fish in 2006 was 80. Since 2001, Wr means have ranged from 79 to 84.

The December striped bass gillnetting also yielded 87 catfish. Blue catfish (60) dominated the catch, followed by channel catfish (16) and flathead catfish (11)

Fall hydroacoustics and purse seine Average forage fish densities in the six zones of Lake Norman ranged from 2,008 (Zone 6) to 8,240 (Zone 5) fish/ha in September 2006 (Table 5-6). The shallow nature of the riverine Zone 6, and resulting limited habitat available for acoustic sampling, complicates discussion 5-5

of fish densities in this uppermost zone of Lake Norman. The lakewide population estimate in September 2006, approximately 61.8 million fish, was comparable to annual estimates since 1997 and well above the lowest estimate of 47.1 million recorded in 2004 (Figure 5-9).

No trends have been noted in lakewide pelagic fish population estimates in Lake Norman from 1997 through,2006. Zones 4 and 6 population estimates continue to remain below other zone estimates.

Purse seine sampling in 2006 indicates that the forage fish population estimated by hydroacoustics was comprised of 94.9% threadfin shad and 5.1% alewives (Table 5-7). As in 2005, no gizzard shad were collected in the 2006 purse seine samples, and the modal length of threadfin shad was between 41 and 45 mm in 2006 (Figure 5-10). Alewives were first detected in low numbers in 1999 and increased to approximately 25% of the pelagic forage fish community by 2002. The percent composition of alewives declined from 2002 to 2005, however, increasing to approximately 5.1% of the forage fish catch in 2006. The overall increase and subsequent decrease in the percent composition of alewife was concurrent with an increase in the threadfin shad modal length class and subsequent decrease to values measured prior to the alewife introduction.

Crappie trap-net study Duke Energy and NCWRC personnel collected 306 black crappie from 60 overnight trap-net sets in Lake Norman in 2006. No white crappie were collected.

FUTURE STUDIES The only requested change to the fish portion of the 2007 Lake Norman Maintenance Monitoring Program is the implementation of additional purse seine sampling in late June/early July to assist NCWRC in evaluating the changing forage fish community.

SUMMARY

In accordance with the Lake Norman Maintenance Monitoring Program for the MNS NPDES permit, specific fish monitoring programs continued during 2006. Spring electrofishing indicated that 13 to 17 species of fish and two hybrid complexes comprised fish populations 5-6

in the three sampling areas, and numbers and biomass of fish in 2006 were generally similar to those noted annually since 1993. Largemouth bass numbers and biomass continue to decline in recent years and the 2006 numbers and biomass were the lowest recorded since sampling began in 1993. During 2006, the number of summer striped bass mortalities (six) and winter mean relative weight (80) were similar to those of previous years. Hydroacoustic sampling estimated a forage fish population of approximately 62 million in 2006, comparable to previous years. Although purse seine sampling indicated a slight increase in the percentage of alewives in 2006, the -percent composition was much lower than in years immediately following their 1999 introduction. During 2006, threadfin shad lengths returned to pre-alewife introduction sizes. Trap netting indicated little change in the crappie populations in Lake Norman.

5-7

Table 5-1. Common and scientific names of fish collected in Lake Norman, 2006.

Common name Scientific name Alewife Alosa pseudoharengus Gizzard shad Dorosoma cepedianum Threadfin shad Dorosoma petenense Whitefin shiner Cyprinellanivea Common carp Cyprinus carpio Golden shiner Notemigonus crysoleucas Spottail shiner Notropis hudsonius Quillback Carpiodes cyprinus Shorthead redhorse Moxostoma macrolepidotum Blue catfish Ictalurus furcatus Channel caffish Ictaluruspunctatus Flathead catfish Pylodictis olivaris White perch Morone americana Striped bass Morone saxatilis Redbreast sunfish Lepomis auritus Green sunfish Lepomis cyanellus Warmouth Lepomis gulosus Bluegill Lepomis macrochirus Redear sunfish Lepomis microlophus Hybrid sunfish Lepomis hybrid Spotted bass Micropteruspunctulatus Largemouth bass Micropterussalmoides Hybrid black bass Micropterushybrid Black crappie *Pomoxis nigromaculatus Tessellated darter Etheostoma olmstedi Yellow Derch Perca flavescens 5-8

Table 5-2. Numbers and biomass of fish collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late March to early April 2006.

MSS REF MNS Taxa N Kg N Kg N Kg Gizzard shad 3 1.79 Threadfin shad 195 0.91 23 0.08 Whitefin shiner 9 0.04 15 0.03 .4 0.02 Common carp 4 12.13 11 22.11 4 7.85 Golden shiner 1 < 0.01 Spottail shiner 15 0.12 2 0.02 Quillback 1 1.28 1 1.43 1 1.31 Shorthead redhorse 4 3.18 Channel catfish 1 0.89 4 1.49 5 1.77 Flathead catfish 2 0.19 3 0.11 1 < 0.01 Striped bass 1 1.54 Redbreast sunfish 149 2.85 389 5.78 186 2.88 Green sunfish 12 0.16 1 0.01 Warmouth 6 0.04 24 0.40 23 0.15 Bluegill 500 5.54 308 3.15 358 3.85 Redear sunfish 85 6.20 47 3.22 30 3.94 Hybrid sunfish 31 0.73 25 0.86 27 0.53 Spotted bass 41 8.38 31 11.23 65 15.82 Largemouth bass 58 25.37 26 16.78 13 7.88 Hybrid black bass 3 0.75 1 0.39 Black crappie 2 0.97 Tessellated darter 1 < 0.01 Yellow perch 1 0.03 Total 924 68.81 1,087 69.34 742 48.02 Table 5-3. Mean total lengths (mm) at age for spotted bass (SPB) and largemouth bass (LMB) collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late March to early April 2006.

Age Taxa Location 1 2 3 4 5 6 7 8 9 SPB MSS 185 307 383 440 REF 162 327 388 417 MNS 186 288 392 393 488 LMB MSS 184 347 346 408 413 405 416 371 461 REF 180 300 363 378 430 417 MNS 169 308 361 402 475 459 5-9

Table 5-4. Mean total length (mm) at age for largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman from late March to early April 2006.

Age Location and year 1 2 3 4 MSS 1974-781 170 266 310 377 MSS 19932 170 277 314 338 MSS 19942 164 273 308 332 MSS 20033 216 317 349 378 MSS 20044 176 309 355 367 MSS 20055 190 314 358 396 MSS 2006 184 347 346 408 REF 19932 157 242 279 330 REF 19942 155 279 326 344 REF 20033 139 296 358 390 REF 20044 143 288 364 415 REF 20055 139 307 357 386 REF 2006 180 300 363 378 MNS 1971-781 134 257 325 376 MNS 19932 176 256 316 334 MNS 19942 169 256 298 347 MNS 20033 197 315 248 389 MNS 20044 170 276 335 370 MNS 2005' 136 342 359 429 MNS 2006 169 308 361 402 1Siler 1981 ; 2 Duke Power unpublished data; 3 Duke Power 2004; 4Duke Power 2005; 5 Duke Energy 2006 Table 5-5. Dead striped bass observed in Lake Norman during weekly surveys in July and August 2006.

Date Number Zone Total length (mm)

Jul 20 2 1 592 3 602 Jul 24 1 1 576 Aug 7 2 1 435 2 574 Aug 22 1 3 610 5-10

Table 5-6. Lake Norman forage fish densities (Number/hectare) and population estimates from hydroacoustic surveys in September 2006.

Zone Density (N/ha) Population Estimate 1 2,930 6,683,330 2 3,481 10,728,790 3 6,084 21,023,384 4 4,091 5,036,021 5 8,240 17,353,440 6 2,008 959,824 Lakewide total 61,784,789 95% Cl 58,266,596 - 65,302,982 Table 5-7. Total numbers (N) and percent composition of forage fish, and modal length class of threadfin shad collected in purse seine samples from Lake Norman during late summer/fall, 1993 - 2006.

Species Composition Threadfin shad modal Year N Threadfin Gizzard Alewife length class (mm) 1993 13,063 100.00% 0.00% 0.00% 31-35 1994 1,619 99.94% 0.06% 0.00% 36-40 1995 4,389 99.95% 0.05% 0.00% 31-35 1996 4,465 100.00% 0.00% 0.00% 41-45 1997 6,711 99.99% 0.01% 0.00% 41-45 1998 5,723 99.95% 0.05% 0.00% 41-45 1999 5,404 99.26% 0.26% 0.48% 36-40 2000 4,265 87.40% 0.22% 12.37% 51-55 2001 9,652 76.47% 0.01% 23.52% 56-60 2002 10,134 74.96% 0.00% 25.04% 41-45 2003 33,660 82.59% 0.14% 17.27% 46-50 2004 21,158 86.55% 0.24% 13.20% 51-55 2005 23,147 98.10% 0.00% 1.90% 41-45 2006 14,823 94.87% 0.00% 5.13% 41-45 5-11

• Electrofishing locations A Purse seine locations 5

..- :Z~re.!3.i +*,:n,, 2' Zoneý 3 La'e

~ii* Cow~sFr t-iyd~rlo

• Stetionr Figure 5-1. Sampling locations and zones in Lake Norman associated with fishery assessments.

5-12

E Co 1996 1997 1999 2000 2001 2002 2003 2004 2005 2006 Year 387 200-180- REFj

[MNJ

,1604 140+

E 8 120- 'Ný 0

100-80-7RR 60-4 1 7 -I 404 20m

- I I I I

I 1

I I I I 1.I I 1 [Ii I I I I 1993 1994 1995 1996 1997 1999 2000 2001 2002 2003 2004.2005 2006 Year Figure 5-2. Numbers and biomass of fish collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 1993 - 2006.

5-13

140 120 100 E

0 00 80 Z

6 60 40 K

J.K&

20 0 11 2001 2002 2003 2004 2005 2006 Year 18 -r 16 -REF K

oMNSI 14 12 E

o0 10

-)

6 4

2 0 - L-2001 2002 2003 2004 2005 2006 Year Figure 5-3. Numbers and biomass of spotted bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 2001 - 2006.

5-14

25-,

uREF 20+

15-+-

-1 10-I-5-

0+

<150 150-199 200-249 250-299 300-349 350-399 400-449 >450 Length group (mm) 25 -r U REF 20+-

E 15-I- M

-I 10-I-MIN 5- MENIN\

m 0

]

<150 150-199 200-249 250-299 300-349 350-399 400-449 >450 Length group (mm)

Figure 5-4. Size distributions of spotted bass and largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 2006.

5-15

100 T [FiSP-SS 90 I REl 80-I-MEN-70+

3: 60 +

50 +

R0 40-C',

30-20-10-I-0+ H- ,x,. 1I I t 4 -I -i 100-149 150-199 200-249 250-299 300-349 350-399 400-449 >450 Length group (mm) 100 90-80+/-

70+/-

60+

50-+

0) 40--

2) 30+/-

20 1-10+

0+ -F 150-199 200-249 250-299 300-349 350-399 400-449 >450 Length group (mm)

Figure 5-5. Mean relative weights (Wr) for spotted bass and largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MNS) in Lake Norman, 2006.

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300 250 -[-IY!.lTh 200 E

0 c 150 z6 100 50-0 +

1993 1994 1995 1996 1997 1999 2000 2001 2002 2003 2004 2005 2006 Year 70-60 50 E

80 40 co Ci)

= 30 cm 20-10 01 1993 1994 1995 1996 1997 1999 2000 2001 2002 2003 2004 2005 2006 Year Figure 5-6. Numbers and biomass of largemouth bass collected from electrofishing ten 300-m transects each, at three areas (MSS, REF, MINS) in Lake Norman, 1993 -

2006.

5-17

100 T g Spotted bass 90+

• Largemouth bass

• Hybrid bass 80oI4 70 -

E 0

0 60+

50-d 40+

z 30+

201-10--

0-2005 2006 Year Figure 5-7. Total number of young-of-year black bass collected from electrofishing five 300-m transects each, at three areas (MSS, REF, MINS) in Lake Norman, 2005 and 2006.

700 90 600 85 500 80 400 75 S300 70 200 65 io 0 60 1 2 3 4 5 6 7 10 Age Figure 5-8. Mean total length and mean relative weight (Wr) for striped bass collected from Lake Norman, December 2006. Numbers of fish associated with mean length are inside bars.

5-18

100 90 80 70 ci, C

0 60 ci, 50 0

.0 40 E

z 30 20 10 0

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year Figure 5-9. Zonal and lakewide population estimates of pelagic forage fish in Lake Norman, 1997 -2006.

200 -

180 -

160 -

/

/

140 -

L- 120 -

Z E 100 80 ALE 7

/

/

60 -

40 - /

/

20 -

/

n /

30 40 50 60 70 80 90 100 110 Length group (mm)

Figure 5-10. Size distributions of threadfin shad (TFS) and alewives (ALE) collected in purse seine surveys of Lake Norman, 2006.

5-19

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