ML20085M640

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Environ Study of Lake Anna & Lower North Anna River,Annual Rept for 1988,Including Summary of 1986-1988
ML20085M640
Person / Time
Site: North Anna  Dominion icon.png
Issue date: 12/31/1988
From:
VIRGINIA, COMMONWEALTH OF
To:
References
RTR-NUREG-1437 AR, NUDOCS 9111110260
Download: ML20085M640 (123)


Text

{{#Wiki_filter:_ _ __ _ __ - __ - _-_____ __ _______ _ Yh Ms<r 5 l1tbt! L I - I ENVIR0!afENTAL STUDY OF LAKE AliNA l AND THE LotTER NORTH AN!!A RIVER I I I I AN!iUAL REPORT FOR 1988 INCLUDING

SUMMARY

OF 1986-1988 I I I I Prepared by: WATER QUALITY DEPARTMENT COF"0 RATE TECHNICAL SERVICES I i gugg soimi g im c eon

E i Table of Contents I -. I Page-Executive Sunnary ......................................... i list of Figures ........................................... iii List of Tables ............................................ Vi Introduction .............................................. 1 Station Operation ......................................... 3 Lake Anna ...................... . . . . . . . . . . . . . . . . . . . . . . . . . 6 i Water Quality ........................................ 6 Fish ................................................. 13 Macrobenthos ......................................... 53 Chlorophyll (a) . . . . .................................. 68

                                                                                                         !!o r t h Ann a R iv e r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .                                                                               76 Uater Quality ........................................                                                                         76 Fish ................... .............................                                                                        78 Study Plan Recommendations - 1989-1991 ....................                                                                                                                                 99 Literature Cited ................)                                                                                                    . . . . . . . . . . . . . . . . . . . . . . . .       102 5

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t l t l Executive Summary Following the successful completion of the North Anna Power Station 316(a) demonstration in 1984-1985, Virginia Power agreed to continue certain environmental monitoring studies on 1.cke Anna l and the lower North Anna River. This study program would be reviewed every three years for possible revision and change in scope. Data collected in 1988 are presented in this report, summarized with the preceding two years' data and compared to histori::a1 data bases. Overall the analysis of the data collected in 1988 ::uggest I no major changes have occurred to the lake or river ecosystems,  ; Results of the three-year study indicate that Lake Anna and the North Anna River contain healthy, well-balanced ecological g communities which have changed little since the 316(a) study. Station operation, water quality, chlorophyll (a), Corbicula, and fish community data for this period were similar I to previous years. Crowth rates for largemouth bass and striped bass in the lake eud smallmouth bass in the river continue to equal or exceed published state averages. Smallmouth bass continue to expand their range upstream in the North Anna River. ! In view of the stability of the lake and river ecosystems and the large data bases accumulated from these studies, Virginia

Fower proposes a reduction in sampling effort for the next three-year study period (1989-1991). These reductions include i

the elimination of duplicate effort in the water quality program, the discontinuance of the chlorophyll (a) and C_orbicula sampling _t_

i programs and a reduction of effort in the downstream game fish distribution sampling programs. Fish population and game fish age and growth studies on the lake and river *.till continue as will the fish structure program. A data summary report will be submitted each year with three-year a review for possible revisions. Specific recot:mendations and justifications ' are presented in section 9.0 of this report. E I G 4 E I t E I E I E

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I 1 I, List of Figures Figure 11 umber Title Page i 1 North Anna Units 1 5 2 monthly mean power level, 1978 to 1988....................................... 1 2 Approximate locations of water quality sampling stations Lake Anna, Virginia...................... 7 1 3 Approximate locations of fixed ENDECO temperature recorders on Lake Anna............................. 8 4 Location of electrofish and gill net stations...... 14 5 Gill net results for Lake Anna during 1988, percent by number and weight....................... 16 6 Gill net results for the WTF during 1988, percent by number and weight..............-........ 17 7 Electrofish results for Lake Anna during 1988, percent by number and weight....................... 21 8 Electrofish results for the WTF during 1988, percent by number and weight....................... 22 9 Composition of largemouth bass collections from 5 Lake Anna, 1986-1988............................... 26 10 Composition of bluegill collections from 1 Lake Anna, 1986-1988............................... 27 11 Composition of black crappie collections from { Lake Anne, 1986-1988............................... 28 12 Catch per unit effort by electrofish and gill net, Lake Anna, 1981-1988.......................... 30 13 Lake Anna fisheries' to ta l r. .b e r , total. e weight for all species and families, !g 1986-1988.......................................... 31 14' Lake Anna electrofish results, percent of total catch, 1986-1988................................... 32 l 15 Electrofish results for Lake Anna percent by l number, 1986-1988.................,. ................ 34 l lt - . . .

1 1 Figure Number Title Pace 16 Gill net results for Lake Anna, percent of total catch, 1986-1988............................. 35 17 Meankrowthcurvesoflargemouthbasscollected in La e Anna, VA from 1978 to 1988................. 42 18 Mean growth curves of largemouth bass collected in the North Anna LTHTF, VA from 1978 to 1988. . . ... 43 19 Mean back calculated lengths for striped bass collected from Lake Anna in 1988................... 48 20 Faan back calculated lengths for striped bass a collected from scale data. Lake Anna, 1986-1988.... 49 g 21 Mean back calculated lengths for striped bass collected from otolith data for Lake Anna, 1986-1983.......................................... 50 22 Length frequency distribution of 316(a) and a post 316(a) striped bass collections............... 55 g 23 Average striped bass condition factors, by quarter and age group for the period 1986 1988..... 57 24 Amounts of habitat available to Lake Anna striped bass during August, 1988........................... 58 sa > 25 Chlorophyll (a) concentrations from three stations in Lake Anna in 1988..........................,,... 70 26 Chlorophyll (a) concentrations from three stations in the WHTF in 1988................................ 71 27 Location of the two continuous temperature re'- corders (x), and two monthly instantaneous temp-erature locations (o), on the North Anna River..... 79 28 Locations of North Anna River fish sampling stations........................................... 80 29 Number of fish collected from the North Anna

         ,   River during forage fish electrofishing surveys, 1981-1988, by collection year......................       83           p, 30    Number of fish species collected from the North                       4 Anna River durinP, forage fish electrofishing surveys, 1981-1988, by collection year.............       86
                                                                                    .a n _

I t E Figure 5 Number Title Page l 31 Mean bankside channel densities (No./100m2) of smallmouth bass and largemouth bass greater than 120 mm total length estimated for NAR-3 1987 i and 1988...............................,........... . 90 32 Mean bankside channel densities (No./100m8) of smallmouth bass and largemouth bass greater than I, 120 mm total length estimated for NAR-3 1987 and 1988................................,........... 91 5 33 Mean bankside channel densities (No./100mt) of smallmouth bass and largemouth bass greater than 120 mm total length estimated for NAR-5. 1987 and 1988........................................... 92 34 Cover utilization preferences of smallmouth bass and largemouth bass derived from cover availa-bility and cover use data obtained from NAR-3, NAR-5 in 1987 and 1988............................. 95 9

I 1 - List of Tables I> I Table Number ,T_i,tle i Page 1 Seasonal sum =ar of North Anna Power Station operation, 1987 1988..................

                                                                                         ............              5 1,         2 Seasonal temperature and dissolved oxygen profiles for Lake Anna,                    1988......................                      9 3

1 Summary of North Anna fixed recorder tempera-tur e da .: a du rin g 19 8 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Numbers net and weights of fishes collected by gilt f rom Lake Anna and the WTF, 1988. . . . . . . . . . . . . 18 5 Nu.sber and weights of fishes collected by electrofish from Lake Anna and the WTF,1988. . . . . 23 6 Mean backcalculated lengths of largemouth bass I 7 collected from Lake Anna 19 8 8. . . . . . . . . . . . . . . . . . . . . and the WTF during

                                                                    .........................                    38 Meanbackcalculatedlengrom1986to1988ths collected in Lake Anna                                                 of largemouth
                                                                                           ..........            39 bass 8          Mean backcalculated lengths of largemouth bass collec ted in the WTF from 1986 to 1988. . . . . . . . . . .                              40 9         Mean condition factors for largemouth bass collected from Lake Anna and the WTF during 1987 and           1988.....................................                             44 10          Significance of differences between scale and otolith menn lengths..............................                                         51 11         Significance of differences between 316(a) and post 316(a) mean lengths..........................                                          53 12      Mean lengths for cluster groups in length frequency analyses................................                                           59 13      Number                   of citation stri Anna..............       ped...........................

bass caught from Lake 60 14 Corbicula fluminea collected in Ekman dredge samples from Lake Anna and the 19 8 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . W. . TF , V A dur in g

                                                                              .................                 64

i Table Number Title Page 15 Corbicula fluminea collected in Ekman dredte samples f rom Lake Anna and the bHTF, VA. . . . . . . . . . . 66 16 Corbicula f'uminea ( 7.5mm) present lar lections in co er than from si::e class 1 l and the kHTF......................... Lake Anna

                                                   .............                            67 17    Mean chlorophyll (a) values (m            from Lake Anna during    1988..............g/m2)
                                          ....................                              72 18    Mean chlorophyll (a) values (mg/m2) from Lake Anan and the kmTF from 1985 to 1988...............                                   73 19    Chlorophyll (a) in the phyto Anna, VA, during 1988....... plankton      at Lake
                                        ......................                              75    ls 20 Number of fish collected from the Nortn Anna River during forage fish electrofishing surveys, 1981-1988, by month of     collection.................                               84 21 Number of fish collected from the North Anna River  during forage fish electrofishing surveys, 1981-1988, by year of collection..................                                    87 22    Number of smallmouth bass and largemouth bass observed during 1987 and 1988 snorkel surveys.....                                  88 23    Monthly mean and maximum densities (No./1002)                                               km of smallmouth bass and largemouth bass estimated                                            g from 1987 and 1988 snorkel survey observations....                                  93 24    Habitat availability data for NAR-3, NAR-4, and NAR-5, obtained during     1988.......................                              96 25    Mean back-calculated total lengths (en) for smallmouth bass collected from the North Anna River, 1983-1988, by years combined....... .............................

year class and for all 98 I 1 I n

1

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3 1.0 Introduction In 1972, Virginia Power (the company) impounded the North Anna River creating Lake Anna, a 3885 hectare (9600 I acres) reservoir (lake) that provides condenser cooling water for Virginia Power's North Anna Nuclear Power Station. Adjacent to Lake Anna is a 1376 hectare (3400 acre) Waste Heat Treatment Facility (WHTP) that receives the cooling water and transfers excess heat from the water to the atmosphere before discharge into the lower reservoir. Aquatic monitoring studies have been conducted on Lake Anna since its inception. In January of 1984 the Company initiated an extensive Section 316(a) demonstration study (P.L. 92-500) to determine if effluent limitations more stringent than the present limitations on thermal discharges from the power station were necessary to assure the protection and propagation of a balanced, indigenous community of shellfish, fish and wildlife in Lake Anna and the lower North Anna River. The final report (Virginia Power, 316(a) Report, 1986) successfully demonstrated that the operation of the power station had not resulted in

                                                             " prior appreciable harm" to the biological com= unity.                                 The Virginia Water Control Board (VWCB) accepted the study as a successful demonstration in September 1986.

Subsequent to the 316(a) study, Virginia Power agreed to continue a reduced level of environmental monitoring on Lake Anna and the lower North Anna River as part of a resource management and enhancement program. The follow-up _ _ _ _ _ . _ _ _ _ _ . - - - - _ - - - - - - - - - - - - - - - ~ ' - ~ - ' ' ' '

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I monitoring program was designed to collect data which would provide a ceans of verifying the conclusions developed from the 316(a) study and measure any changes that might occur in future years. This report discusses the findings for 1988, and succarizes g findings of studies conducted over the three-year (1986-1988) period following the conclusion of the North Anna 316(a) study. Study recocuendations for the next three-year period (1989-1991) are also included. I I I I 5 l t i E l l l t 5

l 2.0 Station Operation The North Anna Power Station operated at or above 80% of its total capacity for most of 1988 (Figure 1) and between 75-100% of generation capacity during all quarters of the year (Table 1). Station operation during 1988 was I similar to that of 1985 and 1986. demonstrated these levels of Past studies have operation have no adverse impact on the ecology of the lake (Virginia Power 1986, 1987). No changes are anticipated in station operations in the future. I I, I lI I !3 lI - !8 I lI 1

FIGURE 1. N,0RTH ANNA UNITS 1 & 2 MONTHLY MEAN POWER LEVEL 1978 TO 1988 MHi s 10- . a - u

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i 5 Table 1. Seasonal strrary of ! brth Anna Pcur Station operatico (percent of total statim load), 1978-1988. YEAR UWER SPRDC SIMER FA11 1978 0 23 42 45 1979 43 31 44 0 1980 31 37 53 65 1981 46 80 67 82 h 1982 78 26 19 48 1983 53 58 96 84 1984 76 64 16 66 1985 87 96 82 62 It 1986 75 88 62 97

    , 1987                 92                  45                 23                47 1988                 75                  99                 94                97 i

Quarters at 75-100: 6 4 3 4 I I . g I

E 3 . 0. Water Quality - 1.ake Anna In accordance with the post 316(a) monitoring agreement between the Company and the VWCB, water quality paramaiters of temperature and dissolved oxygen were monitored on a seasonal (quarterly) basis during 1988, at stations in the lower lake, mid-lake and upper lake (Figure 2). 3.1 Temperature Temperature / plume surveys collected instantaneous temperature data for the assessment of seasonal thermal stratification patterns. The data collected in February, May, August and November of 1988 are presented in Tabla 2. The data demonstrate that 1.ake Anna exhibits little or no thermal stratification during the first and last quarters of the year, ne data also demonstrate the presence of a spring thermocline at approximately 8-9 meters which dis- g appears from most of the lake during the summer months N except in , the lower lake where it is at approximately 15 meters. The 1988 stratification patterns are similar to past years and are typical for Lake Anna (Virgini- 'over, 1986). Water quality temperature data is supplemented with data collected from Virginia Power's continuous recording

                           , ENDECO instruments which record surface temperatures on an hourly basis at the sta: ions in Figure 3. ENDECO tempera-                                             g ture data is st bmitted to the VWCB in addition to plume survey data on a quarterly basis,               as required in NPDES Permit Number VA 0052451.            A summary of these data for the
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                                                                                                                       ~ M           M   W       (     [ U Table 2. Seasonal temperature and dissofwed oxygen profiles for Lane Anne, 1988.
                      . MONTH = FEBRttARY                                                                         MnNTH = MAY STATl0H = DAM       STATlON = $NTAkts        STATION = RT. 208                    STATION = DAM          STATION = INIANTS        STATION = ST. 208 DEPfH IEMP        DC    DEPTH TEMP       00      DfPTH TEMP     DO                DEPTH TEMP        00       MPTH TIMP          DO    OIPTH TfW       (M 0      7.6  11.8       0     5.5   12.2         0     3.9  12.4                  0     23.8     8.2         0      23.8     8.9       0   24.3 , 9.2 1      7.6  11.8       1     5.4   12.2         1     3.8  12.4                   1    23.8     8.2          1     23.6     9.0        1  24.0    9.1 2     7.6   11.8       2     5.2   12.2         2     3.8  12.4                   2    23.7     8.2          2     23.5     8.8       2   23.9    9.2 3     7.6   11.8       3     5.2   12.2         3     3.8  12.4                   3    23.6     8.1          3     23.5     8.8       ;   23.7    9.3 4      7.6  11.8       4     5.2   12.2         4     3.8  12.4                  4     23.6     8.1         4      23.4     8.8       4   23.6    9.2 5     7.6   11.8       5     5.2   12.2         5     3.8  12.4                  5     23.5     8.0         5      23.3     8.8       5   23.1    9.1 6     7.6   11.8       6     5.2   12.2         6     3.8  12.4                  6     23.5    8.0          6      22.2     8.4       6   72.5    8.5 7     7.6   11.8       7     5.2   12.2         7     3.8  12.4                  7     23.4     7.9         7      21.7     8.0       7   22.1    7.9 8     7.6   11.8       8     5.2   12.2         8     3.8  12.4                  8     23.2    7.7          8      21.0     7.5       8   21.5    7.5 9     7.4   11.8       9     5.0   12.2         9     4.0  12.4                  9     22.7     7.6         9      20.1     6.6       9   20.0   5.7 10      7.3   11.8     to     4.8    12.2       10      4.0  12.2                to      21.1     7.5       to       19.2     57      to    19.3    4.6 11      6.8   11.8     11      4.8   12.2       11      4.0  12.4                11      19.5     7.2       11       18.7     5.1     11    18.4    3.1  l 12      6.7   11.8                                                               12      18.0    6.7 13      6.7   11.8                                                               13      17.4    6.3 14      6.5   11.8                                                               14      16.9    6.0 15      6.5   11.8                                                               15      16.6    5.8 16      6.5   11.8                                                               16      16.5    5.8 17      6.5   11.8                                                               17      16.4    5.7 18      6.5   11.8                                                               18      16.0    5.4 19      6.5   11.8                                                               19      15.7    5.3 K) NTH = AtOf5i                                                                   NnNTH = NOVT MiT R STATION = DAM       STAllDN = INTtKIS        STATION = RT. 238                   STATION = DAM           STATION = INTAaES         STATION = RT. 206 DfPTH TEMP       00    DEPTH TEMP       DO      DEPTH TEMP     DO                M PTH TEW         00       OfPTH TTNP         00     DIPTH TEMP     DO O    30.5     5.6     0     29.5    5.6        0     29.3   6.3                  0     15.8    9.1          0      13.9     9.3       0   13.1    9.6 1    30.5     5.6      1    29.5    5.6         1    29.3   6.3                  1     15.8    9.1          1      13.9     9.3       1   12.9    9.6 2    30.5     5.6      2    29.5    5.6        2     29.3   6.3                  2     15.8    9.1          2      13.8     9.3       2   12.6   9.6 3    30.5     5.6      3    29.4    5.6         3    29.3   6.3                  3     15.8    9.1          3      13.7     9.3       3   12.6   9.6 4    30.5     5.6     4     29.4    5.6        4     29.3   6.3                  4     15.8    9.1          4      13.7     9.2      4    12.5   9.6 5    30.5     5.6     5     29.4    5.6        5     29.3   6.3                  5     15.7    9.1          5      13.7     9.3      5    12.5   9.5 6    30.5     5.6     6     29.4    5.6        6     29.2   6.0                 6      15.7    9.1         6       13.6     9.2      6    12.4   9.5 7    30.5    5.6      7     29.4    5.6        7     29.2   6.2                  7     15.6    9.1          7      13.5    9.2       7    12.4   9.5 S    30.5    5.6      8     29.3    5.4        8     29.5   6.5                 8      15.6    9.1         8       13.2    9.2       8    12.4   9.5 9    30.5    5.6      9     29.1    5.8        9     29.1   6.5                 9      15.3    9.1         9       13.2    9.2       9    12.4   9.5 10     30.4    4.5     10     29.0    6.1       TO     29.0   6.4                to      15.2    9.1        to       13.1    9.2      to    12.4   9.5 11     30.1    5.1     11     29.9    6.0       11     28.9   6.0                11      15.0    9.0        11       13.0    9.6     11     12.3   9.9 12     30.0    4.8     12     28.9    6.0       12     28.8   5.0                12      15.0    8.9 13     29.9    4.6     13     28.9    6.0                                        13      15.0    8.9 14     28.9    4.2                                                               14      14.9    8.8 15     27.4    0.1                                                               15      14.3    8.0 16     25.9    0.1                                                               16     14.2     8.1 17 -   24.8    0.1                                                               17     14.2     8.2 0.1                                                               18     14.2     8.2 18    23.4                                                                              14 2     82 0.1                                                               19 19    22.2                                                                                                                                              _

I I lake and the MF is presented in Table 3. These data in<H 6e that Lake Anna had a maximum recorded surface temperature of 31.4'C in August 1988 and a minimum of 3.7'c in January 1988. These extremes were similar to 1987 (33.2*C and 2.0'C) and 1986 (30.9'c and 3.6*C) data. 3.2 Dissolved Oxygen I Quarterly surveys were conducted to assess seasonal stratification patterns for dissolved oxygen. These data, when analyzed in conjunctinn with temperature data, provide information on the aquatic habitat available to the lake's obligate aerobic organisms. The data for 193R indicate Lake Anna levels for dissolved oxygen (Table 3) were typical of past years. Oxygen concentrations were limiting to deep water habitat utilization during the summer months (July-August) of 1988 when values fell below 2.0 ppm. This in stratification pattern for dissolved oxygen has been E reported for Lake Anna since 1978 (Virginia Power, .986). Recommendations for the Study Period 1989-1991

1) The historical data collected for temperatura and dissolved oxygen have been consistent for the period of study, therefore negating the need for continued effort
                                                                                     ,        in these areas. The surface temperatures will continue to be monitored        lakewide    by   the    ENDECO  continuous recorders and dissolved oxygen measurements will be l                                                                                              collected during routine biological surveys.

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E Table 3. Svemmary of North Anna fi ned recorder teenperature dat a during 1968 Yetwes are means of daily high, seen, and to= =alves (la degrees Celsles). All Instruments except for NA15T10 are located at the surface. NAf5T10 is at eld-depth. Hour 6 ef data cet tet tid are shoon. HARCH APRit MAY JUM fin Y AUCHST STPTINbf R OCITT R $DVf 9 ftir Of(IMRf R STAllON NO. T[PE JANUARY TilWUARY 10.0 16.4 21.9 27.1 29.9 30.8 25.7 17.9 12.2 8.8 NA17195T 6 HiQi 3.7 4.9 11.9 8.5 HfAN 3.5 4.6 9.1 15.7 21.1 26.3 29.1 30.2 25.c 17.5 i 4.3 0.7 15.1 20.4 25.6 28.6 29.7 24.6 17.2 11.5 8.4 l TOW 3.3 144 720 153 ! HOURS 744 694 744 720 744 789 744 744 759 4.7 16.3 22.0 27.3 30.2 31.1 25.6 17.9 12.2 9.t NAL719MI 5 HIGl 3.7 9.8 17.5 11.9 8.9 HEAN 3.5 4.4 9.1 15.6 21.1 26.4 29.3 30.4 25.0 4.1 8.5 15.0 20.4 25.6 28.7 M.8 24.5 17.1 11.5 8.6 t Ott 3.3 744 720 744 720 155 HOURS 744 693 744 720 744 719 744 9.5 15.8 21.6 27.0 29.7 30.4 26.1 19.3 34.3 13.1 NAL206T 4 HIOi 4.0 4.8 3.8 4.5 8.9 15.3 20.9 26.2 29.0 29.8 25.7 19.0 14.0 10.9 HEAN 10.7 4.2 14.9 20.3 25.6 28.5 29.4 25.4 18.7 13.6 LOW 3.5 8.5 742 720 744 720 155 744 694 744 720 744 719 744 HOUR 5 10.1 16.1 21.6 26.8 29.6 30.9 26.3 19.8 14.8 12.0 ELINT 2 NfG1 5.4 5.9 25.8 19.5 14.5 11.s MEAN 5.1 5.5 9.6 15.6 20.9 26.1 28.9 30.3 9.2 15.2 20.3 25.5 28.4 29.9 25.3 19.3 14.3 11.6 10W 4.8 5.2 744 720 857 694 744 720 744 719 744 144 719 HOURS 744 l 10.6 16.3 21.9 27.0 29.8 31.a 26.8 20.3 15.5 12.5 NALTHl5T 1 HlOf 5.8 6.3 20.0 15.2 12.3 5.9 10.1 15.8 21.1 26.2 29.1 36.4 26.2 HEAN 5.6 29.9 25.7 19.8 14.9 12.1 10W 5.3 5.6 9.7 15.4 20.5 25.5 28.5 720 744 719 144 744 719 744 72C 152 HOURS 744 695 744 17.3 22.3 27.1 30.0 31.4 27.6 21.5 16.7 14.1 MLBRPIT 3 $1101 7.7 8.2 12. 21.2 16.4 13.9 7.6 21.5 26.4 29.2 30.7 27.2 NEAN 7.4 g g* 4 g '6.7 28.6 26.8 20.9 16.0 13.6 13W 7.1 7.2 S..u 16.3 20.9 25.8 0.3 744 720 744 719 744 744 720 744 720 154 HLtJR5 744 694 17.5 21.7 29.6 31.' 28.0 22.2 17.5 15.0 NA15110 Hn Of 8.5 8.9 12.5 26.5 17.3 14.8 to 12.2 17.1 21.3 26.1 29.2 31.0 27.8 22.0 HEAH 8.3 8.6 28.8 30.7 27.5 21.8 17.1 14.7 LOW 8.1 8.4 11.9 16.7 20.8 25.6 720 764 719 744 744 718 744 720 154 H0tJR5 744 694 744 20.5 2$.2 2 8. t> 33.3 36.4 37.3 33.9 27.6 23.4 21.0 NADl5C1 7 HIGI 15.9 15.8 31.7 27.4 23.1 20.7 15.3 19.9 23.8 28.2 33.0 36.1 37.1 Mf A4 15.3 35.8 36.8 13.5 27.2 22.5 20.2 14.9 14.9 19.3 23.5 27.9 32.7 10W . 744 719 7% 744 TIS 144 770 157 HOURS 744 694 744 720 23.8 26.7 31.2 34.4 35.2 31.4 25.0 20.8 18.4 NAMfif 2 8 HIGl 11.6 12.0 17.1 18.0 16.6 21.3 26.0 30.6 33.7 34.6 30.8 24.7 -20.4 HEAN 11.1 11.4 24.3 20.0 17.6 10.8 16.1 20.6 25.4 30.0 33.1 34.0 30.4 1DW 10.7 764 744 719 744 720 158 744 694 744 720 744 719 t100R5 20.2 25.3 30.0 32.8 33.7 29.5 23.0 18.6 15.7 HAwHTF3 9 Hloi 9.3 10.4 15.0 29.1 22.5 14.3 15.6 14.4 19.7 24.6 29.3 32.2 33.2 HEAN 8.8 9.4 31.7 32.8 28.7 22.5 18.2 15.4 8.1 8.2 14.0 19.3 24.1 28.7 LOW 744 744 718 744 720 159 744 694 744 720 744 719 HOURS

\

l I

                                                                    $i
               ~
2) Quarterly plume surveys will be continued, as they are

, required by the NPDES Pemit. l I

                                                                       +

1 E ! I' I E' I' E~ E I I I,

                                                                    .E

? 4.0 Fish Experimental gill nets and shoreline electrofishing have been used in Lake Anna since 1972 to assess lake fish populations by collecting fish from the deeper strata of the laku (gill net) and those normally occupying the shoreline habitat (electrofish). Sample station locations are I depicted in Figure 4 Fish were collected quarterly during the post 316(a) study period (February, June, August, and October). Shoreline electrofishing stations were 100m in length and normally included a brush pile , except for the dike stations which were uniformly rocky. Experimental gill nets were set near littoral drop-off areas. Both gill net and electrofish sample procedures have remained constant since 1972, although some station locations have changed due either to shoreline development or alterations in the sampling program. No sampling station changes were made during this three-year study (1986-1988). All fish collected were returned to the laboratory for processing with the exceptien of game fish in good condition which were measured, weighed and released in the field. In the laboratory, up *o 50 individuals per species from each gill net station were measured to the nearest millimeter total length (TL) and weighed to the nearest 0.1 gram.

                                                   ,Those individuals over 50 per species were enumerated and bulk weighed.

l

              ~,                      ,

ORANGE CO. ti cb I LAKE ANNA ( ' w e, h 2KM 7 nonin Anna 2 u.ses ARM i o ,ot,,, SPOTSYLVAfilA CO.

                                                                                       ,TilUILM AN ILL AnD LOUISA CO.                           creek 6                    O nonm ArmA 'h' g*                  eowen o c.n eu, sm 3   '"           '

IME 1 o Ein ..la s... g 1 EVY CilE E K DIKE 2 Wastunglon D.C. _ Dam l'b ,

                                                                                                        ~

w.1, VA i LONER S, e q DIRE 3 LAKE

                         - Waste lleat Treatment Factiety Figure      4.       Location of electrofisin and gill net stations.

W W M W M M M M M M M gm m Em M W m4 M5

I I - All fish collected by electrofishing were returned to the laboratory and separated into size classes, enumerated and bulk weighed. Surface water temperature ('C) and dissolved oxygen (ppm) were recorded for each sample, 4.1 Gill het Results Seventeen species of fish representing seven families g were collected from Lake Anna and the WTF by gill netting operations during 1988 (Table 4). A total of 806 fish weighing 272.8 Kg was collected from four stations in the lake and two in the WTF during four quarterly samples. Of this total, 618 (182.6 Kg) fish were collected in the lake and 188 (90.2 Kg) in the WTF. The dominant species in terms of number collected by gill netting in the lake during 1988 was threadfin shad, porosome petenense, followed by gizzard shad, n. cepedianum, and white perch, Morone americana (Table 4). The dominant species by weight in the lake was channel catfish, Ictalurus punctatus. Figure 5 is a graphical illustration of the numerically dominent and weight dominant species collec'ted by gill netting from the lake during 1988. Figure 6 illus-trates the same dominances for the WTF. During 1988 the shad species supplanted white perch,

                     ,the numerical dominant species collected in 1987, and black L

crappie, Poxcmis nicromaculatus, which dominated in 1986. These data indicate an increase in the number of forage fish available in the lake for 1988. Channel catfish replaced walleye, Stizostedion vitreum, as the dominant species in

i I r nior. 5. Gil het Results _ake Anna-1988 l

                        % by number g

l l LIGEND t M D. potenense 39.6% other 1.87 M 0. . s cisNv. ' .. ? i =l M u. omericano 12.4%  ! M P. nigromoculatus s.8% M l. tunctatus 84 M S. vitroum S.4% M E sotmche 5.3% g

                                                                                    =
1. cotus 2.3%

M C. corpio 1.8% M M. sciotMs 1.*4 l I Gill het Resu ts I, ! Lake Anna-1988 g,

                        % by weight l

t' LEGEND M l. punctatus 29.3% d other 2.4% M 5. vesm ';.1 , M C. corpio 15.9% M l. cotue 8.3% ' M u. solmoides 6.3% { M D. cepedlanum S.3% j 4 u..axatm. s.ex g l

  • w u. ~ s...

M P. nigremoculatus 1.8%

                                        <0 t. .a s u s                              l:

i a W " l 3 I nur. 6. Gill Net Results W.F .T.F. - 19 88

                                                                              % by number

( LEGEND M M. omericono 27.17. M , . r. : *.: s 16 ' 1 M M. sclmoldes 20.2% M C. corpio 97. M D, cepedianum 87. M L. macrochirus 8% d other 1.6% Gi Net Results W.H.T.F.- 19 88

                                                                                % by weight i

LEGEND M C. Corpio 49.4T. k i

                                                                                                     ?, ,, f. ; *. ;* W 4 d.'.45 M M. salmoides 14.3%
                                                   '                                            M D. cepedionum 4.37.

M M. omericano 2.77. M M. sexotills 1.67. d other 1.6% _ _ _ _ _ - _ _ _ . _ _ - - - - - - - - - - - - - - - - - ~ -

Table 4. Humbers and veelghts of fi shes collected t y gill net f rom Lake Anna and the t2 H.T.f'. 19E8 Lake Anna 2/9/88 6/9/88 8/24/88 10/24/88 Totals t Total Species & / wgt (g) &/ wgt.(g) g/ gt (g) g / wgt (g) g/ wgt (g) g / wgt.(g) Dorosoma petenense 5 29.6 9.4 227 Dorosoma cepedianum 1 1.598.9 9 57.5 242 1,695.4 39.2 0.9 4 671.0 6 1,282.9 64 6,438.9 4 1,168.5 78 Morons americana 2 62.8 47 2,368.3 9,561.3 12.6 15.3 Pomonis nigromaculatus 23 648.8 4 416.9 76 3,516.8 12.3 1.9 7 590.8 1 46.1 41 2,121.8 5 483.2 54 8.7 lctelurus punctatus 10 6,292.4 13,562.1 3,241.9 1.8 17 7 12,612.7 15 21,02).8 49 53,495.0 7.9 29.3 Stsrsstedium vitreum 29 38,058.0 3 3,676.0 - - 1,244.0 Hieropterus salmoldes 2 866.1 8 1 33 42,978.0 5.3 23.5 5,129.8 16 1,505.8 6 3,970.9 32 11,472.6 5.2 6.3 Ictclurus catus 2 5.866.5 6 4,309.1 3 2,474.9 2,517.7 Cyprinus carpio 3 14 15,168.2 2.3 8.3 3 9,379.0 4 9,728.0 4 9,979.0 23,086.0 Morone sanattlis 11 1.8 15.9 4 4.720.0 4 814.2 - - 3 1,499.2 11 7,033.4 1.8 3.9 icteturus nebulosus 3 569.9 2 455.0 - - 2 502.4 7 1,527.3 letclurus natalls 2 204.3 3 906.2 - - 1.1 0.8 teposts macrochirus 5 1,110.5 0.8 < 0. 6 1 30.7 1 41.4 - - 2 72.1 0.3 0.1 Esta luctus 1 2,581.0 - - - - Lepomis gulosus - 1 2,581.0 0.2 0.4 1 8.5 - - 1 8.5 0.2 < 0.1 Notropis hudsonius 1 9.7 - - - - -- - t 9.7 0.2 Parco flavescens < 0.1 1 11.3 - - - - 1 11.3 0.2 < 0.1 Totals 72 60,542.1 103 41,980.1 387 37,179.7 56 42,867.1 618 182,569.0 Avg. s/wt per set 18 15,135.5 26 10,495.0 97 9,294.9 14 10,716.8 39 11.410.6 WHIF 2/10/88 6/10/88 8/23/88 10/26/88 Totals  % Total Species & / W tg 3 g/ wgt (g) g/ wgt (g) g / Wgt (g) g/ wta (g) g / wgt (g) Horons americana 9 1,061.2 38 1,068.3 1 59.9 3 219.0 51 2,408.4 27.1 Ictclurus punctatus  !!9 14,819.4 4,961.1 2.7 8 3 690.8 9 3,098.6 49 23,569.9 26.1 26.1 Micrepterus salmoldes - - 10 4,238.9 13 2,721.3 15 5,913.7 38 12,873.9 Cyprinua carpio 70.2 14.3 3 7,9F 0 4 12,089.0 3 7,672.0 7 16,896.2 17 44,592.2 9.0 49.4 Dornsoma cepedianum - - 6 1,459.2 8 2,258.1 1 193.4 15 3,910.7 Ltposts macrochirus 8.0 4.3 1 40.7 13 411.2 1 6.3 15 458.2 8.0 0.5 Morons taxatitis 1 1,417.0 - - - - - - 1,417.0 Ictelurus catus 1 M 6. 4 - - - 1 0.5 1.6 1 548.4 0.5 0.6 StirsatMlum vitrium 1 495.3 - - - - - - 1 495.3 0.5 0.5 Tetals 44 26,276.3 67 23,857.2 41 13,813.3 36 26,327.2 188 90,274.0 Avg. s/=t per set 22 13,138.1 34 11,928.6 20 6,906.6 18 13,163.6 24 11,284.3 mm mm W M 4 MS W W M S M M M M M M M

l terms of weight in 1988, returning to the position it held I in 1986. The gill net results may not be truly represent-t L ative of the total catfish population in the system because catfish may be attracted to dead and dying fish in gill nets thereby inflat tng tne numbers somewhat. Species changes in the number and weight hiararchy of gill net collactions from year to year are not considered unusual due to the relative size of the sampling program compared to the size of the lake, but are important in providing data on major species shifts in fish populations ove*. time. In the WTF the numerically dominant species was white perch, followed by channel catfish and largemouth bass, Microoterus salmoides. White perch was also the numerically dcminant species for the WTF in 1986 and 1987. The weight-dominant species for the WTF in 1987 was common carp, Cverinus carnio, also a repeat of 1987 and 1986 (Table 4). The average number of fish collected per 20-hour gill I net set ranged from 11 at the Levy Creek and WTr ' Stations i to 104 at the North Anna Arm Station (the latter included a ( large sc. col of threadfin shad). Similar to past years, the North Anna Arm Station also yielded the greate t number of fish collected during the year (52% of total). l The highest average weight per set and highest total l

           . weight were collected at the WTF 1 Station (16.9 Kg and 67.8 Kg, respectively) closely followed by the Lower Lake Station (13.7 Kg and 62.8 K E).          The WTF 1 Station had high numbers of large channel catfish, common carp, and large-                          l

R g mouth bass, while a large number of walleye were collected at the Lower 1 Station. When the data are examined seasonally *he greatest . number of fish were collected during late summer (August) in Lake Anna (53 of total collection) primarily due to the presence of large numbers of threadfin shad in the l collections. By weight the February collectiona rank highest (21% of total weight) due to the large number of walleye collected. I 4.2 Electrofish Results Nineteen species representing nine families were collected from Lake Anna and the WTF by electrofishing operations during 1988 (Table 5). A total of 4,562 fishes l weighing 111.7 Kg was collected from five stations in the lake and four in the WTF during the quarterly sampling a periods. Of the 4,562 fish collected during 1988, 2,567 5 (75.7 Kg) were collected in the lake and 1,995 (36.1 Kg) were collected in the WTF. Figures 7 and 8 depict the numerically dominant and weight dominant fish species in both the lake and WTF , respectively, for 1988. Bluegill, Lepomis macrochirus, dominated both numbers and weight in the lake and WTF, as

           , it has for the past several years.                                                               Largemouth bass ranked second in the lake and WTF in both numbers and weight, again repeating results of 1986 and 1987 studies.

The average number of fish per station collected in the ' lake, across all sampling periods, ranged from 61 at the g a

)

         ~

noo,. 7. E ectrofish Results La <e Anna-1988

              % by nurnber LEGEND M     . macrochirus 72.6%

M u.;sm:Hes 7. ' ~ M L. curitus 6.57. M L. microlophus 5.1". M P. nigromoculatus 3.7% M L. gulosus 2.67. d other 2.4% Electrofish Results Lake Anna-1988

                % by weight LEGEND M L macrochirus 44.4%

M M. sc,m ides 'O.c 7 , M L microlophus 13.8% '

 ,                                                P. nigromaculatus 11%

M L ouritus 3.6% M L. gulosus 3.37. M 1. punctatus 1.7% d other 2.7%

i I j n

                             . a. Electrofish Results                                                          I W.F .T.F. - 19 88                                                        l l                                      % by number g

i I LEGEND M L. macrochirus 86%

                                                             $ '.'. .:.mcides 6.c ; l M L. gulosus 3%                                       l
                                   <.                        M L. microlophus 2.8%

M L curitus 1.1% other .5% I Electrofish Results I W. H .T. F. - 19 88 =

                                      % by weight                                                              s.

I LEGEND I M L. macrochirus 57.2% h M '.t..n m:!ces C'7 , M L. gulosus 5.8% i M L. microlophus 2.4% M P. nigromaculatus 1.9% , 1 other 1.7% W

                                          ?                                                                                                                                   U U 1able 5.        Numbers anit -eights of f i shes collec t ed by elect rof f sh f. om t Le Anna and t he W.H.1.r.,1988.

Lake Anna

  • 2/3/88 6/28/88 8/3/88 10/28/68 totain  % Total Species No. / Wgt (g) No. / Wgt (g) No. / Wgt (g) No. / Wgt (g) No. / Wgt (g) No. / Wgt (g) l lepamis macrochirus 810 15,342.1 184 2,409.0 96 1,308.4 774 14,581.5 1,864 33,641.0 72.6 44.4 Micropterus salmoldes 140 11,172.8 10 1,114.8 12 706.4 19  ?,7121.0 181 14,706.0 7.1 19.5 Lepomis auritus 44 1,110.5 23 157.5 38 199.3 61 1,253.6 166 2,720.9 6.5 3.6 lepomis microlog,hus 99 9,725.6 3 88.9 3 52.3 26 555.6 131 10,422.4 5.1 13.8

, Pomo=Is nigromaculatus 11 571.5 48 4,314.5 3 205.4 32 3,200.8 94 8,292.2 3.7 11.0 i teposts gulosue 24 876.3 7 259.2 2 70.7 33 1.255.8 66 2,462.0 2.6 3.3 lepomis gibbosu. 7 133.2 1 56.0 - - 15 268.9 23 458.1 0.9 0.6 Perca flavescens - - 7 186.0 3 78.5 2 51.9 12 317.0 0.5 0.4 Notropis analost<rss 2 3.2 9 28.4 - - - - 11 31.6 0.4 0.1 Dorosoma cepedianem 2 20.6 4 384.7 1 120.5 1 250.0 8 775.8 0.3 1.0 Horone americana - - 3 83.6 - - - - 3 83.6 0.1 1.7 l Ictalurus punctatus - - 1 318.0 1 928.2 - - 2 1,246.2 40.1 40.1 l Notemigonus crysoleucas - - 1 57.2 - - - - 1 57.2 40.1 0.1 1 88.0 1 88.0 40.1 0.1 i letalurus nebulosus - 128.0 1 128.0 40.1 0.2 l tctalurus natalls - - - -

                                     -               -                                                               1 Notropis proene                    1                2.3        -              -          -               -         -              -

3 2.3 40.1 40.1 Ethecstoma olmstedi - - - - 1 2.9 - - 1 2.9 40.1 40.1 Catostomus commersoni - - - - 1 120.7 - - 1 120.7 =0.1 0.2 Totals 1,140 38,958.1 301 9.458.4 161 3,793.3 965 23,346.1 2,567 75,697.6 Avg. #/wt per set 228 7,791.6 60 1,891.7 32 758.7 193 4,669.2 128 3,784.9 WHIF 2/5/88 6/29/88 8/4/88 10/27/88 totals  % Total Species No. / Wgt (g) No. / Wgt (g1 No. / Wgt (g) No. / Wgt ig) Ng. / tgt ig) No. / Wgt ig) tepomis macrochirus 741 9,357.8 88 1,151.1 222 1,389.0 665 8,719.8 1,116 20,617./ 86.0 57.2 gjeropterus salmoldes 53 4,277.4 21 2,031.7 16 966.9 41 3,888.6 131 11.164.6 6.6 38.0 tepomis gulosus 26 1,108.4 - - 9 118.4 25 867.5 60 2,094.3 3.0 5.8 tepomis microlophus 23 411.4 1 54.5 5 18.9 27 382.6 56 867.4 2.8 2.4 tepomis auritus 3 138.5 7 71.9 6 31.7 6 68.0 22 310.1 1.1 0.9

  )omonts nigromaculatus           -                -          1             36.4        -               -         4            634.0       5           670.4      0.3           1.9 34.8                       -          -               -         -              -

2 34.8 0.1 40 0 . 1 totemigonus crysoleucas 2

   )orosoma cepedianus             -                -          -              -          -               -

1 220.0 1 220.0 d0 0.1 0.6 Esom niger 1 55.0 - - - - - - 1 55.0 dLO.1 0.2 30.3 d; 0. 3 <; 0.1 Ittalurus natalls 1 30.3 - - - -  ? 850 3,345.6 118 3,345.6 258 2.524.9 769 14,780.5 1,995 36,064.6 fotals 212 836.4 30 836.4 65 631.2 192 3,695.1 125 2.254.0 Lvg. #/=t per set

I I Lower Lake Station to 236 (962 bluegill) at the Dike 1 Station. Dike stations, as in the past, had larger numbers of smaller fish, primarily bluegill. Similar to previous findings, the North Anna Arm Station demonstrated the g greatest diversity (12 species and seven families) whfle the dike stations exhibited the lowest (five to seven species, one to three families--96% bluegill). The largest average weight per collection and highest total weight was collected at the Thurman Island Station (7.4 Kg and 29.4 Kg, respectively) primarily due to numbers of game and pan fishi specifically, largemouth bass, black erappie and redear sunfish, Locom Q microlochus. Seasonally, more fish were collected during the February survey (1,140). The February collections also yielded the greatest biomass (39.0 Kg). During the warmer months fish normally tend to move into deeper, cooler water

  • and are not as available to shoreline electroshocking. The I lowest numbers of ' fish were collected during the June and August samples (419 fish each) during 1988. However, the August sample had a much smaller total weight than the June sample (6.3 Kg versus 12.8 Kg) further indicating the movement of the larger fish from the shallows into deeper waters as well as the recruitment of young-of-the-year g
     , fishes into the shallows.

I 4.3 Lake Fish Poculation Three Year (1986-1988) Summary t The results of the 1968 electrofishing surveys in Lake Anna and the WHTF duplicate the 1987 survey results: E en

J bluegill and largemouth bass ranked one and two

respectively,in both inshore lake and WTF collections for number and weight. In the 1988 gill net collections shad l and white perch ranked first numerically in the offshore areas, lake and WTF respectively. These results would imply similar fish assemblages in both areas dominated inshore by bluegill (prey) and largemouth bass (predator) populations, while in deeper water there is a large population of shad and white parch (prey) available for the large deepwater predators such as walleye, striped bass, (Morone saxatilis), and channel catfish.

When the gill net and electrofish data are combined for certain selected species and size class distributions are examined, the data indicate that the largemouth bass population is relatively stable with good recruitment to intermediate and harvestable size classes of fish, similar to 1986 and 1987 results (Figure 9). Although the bluegill population still appears to be stunted (Figure 10) the data over the past three years appear to indicate a progressive decrease in the percent composition of young-of-the-year fishes and increases in the intermediate size class and, in 1988, also in the harvest-able size class. This is a trend which will hopefully

             , continue in future years.

The size class data for black crappie are fairly consistent over the past three-year study period (Figure 11) with a low percentage of young-of-the-year fishes collected.

i l l I

     . Figure 9.                   y   7 gg ,,                             :                                    g gy                            ,, a         v

_ V3 :A C- I _A(E AshA $85-:988) t PERCENT OF TOTAL 100 I 80 - l 60 I I l

             --                                       - ' ~ -

40 - - m 20 5 I 0 YOY INT M HAR l SIZE CLASS l M m. es M m . 87 M m . 88 -e- wi. es X g WT 87 -+- WT. 88 YOY < 200:t INT < 300mm. HAR > 300ma I e

                                                                                                                  =

nc

t l lI

                                   ,,y7S..---,

I n . 10. m. .

                                                                       , c.     ,

3  : .. g J _. m _ J .. - _. sA v

                                  ;_A(EA\\A'.E85'.E88:

I . . PERCENTOFTOTAL I 100 I s0 y I s0 . . . . .... . .. . .... . . I 40 -

                                                                                                                                              ~

1 20 l 0 h YOY INT HAR SIZE CLASS g M u . es M u . 87 m u . 88 -e- n. Bs l x n. 87 0 n. Ba g m < i m aso. . nsc. I I ...

4 I qn . n ..

                                                                                                       ....n                           -
                                                                                                                                       ~

Figure 11. . V +

                                                                                                          ,,         g J

4 3 A:K ':lA33:: E JA~:- I

A(iAs\A:E85-:E88; g 100 PERCENT OF TOTAL l

l I B0 ' - - - '- l i 60 E 40 w g 20 _ . . . . . .. .. ...... ...... . ......... ..... 3 I 0 YOY INT HAR g s SIZE CLASS l. E NUM. 86 E NUN. 87 E M. 88 -e- C. 86

                                               -*- WT. 87                -+- U. BB                                                                                                          '

YOY < 130m, INT < 200a. HAR > 200m h E' n. na

I I Gill nets and electrofishing may not adequately sample black crappie, especially young-of-the-year fishes, in any lake especially Lake Anna, but the data do not indicate a major change in the size d!.stribution of this species over the past three years. Catch per unit effort (CPUE) data for electrofish and gill net collections since 1981 are fairly consistent (Figure 12). During the time frame for this particular three-year study period both collection methods have shown a gradual increase in CPUE. When total numbers and weights of fish collected by electrofishing are compared during the three-year study period, the results are remarkably consistent (Figure 13), indicating a stable, uniform inshore fish population dominated by bluegill. Gill nct results are less consistent by demonstrating steadily increasing numbers and veights of fish collected each year during the three-year study period , (Figure 13). However, the number of species and families collected has remained fairly stable, especially over the

  • 1ast two years (Figure 13).

These trends of the two sampling methods continue when the percent of individual species collected during the three-year period are compared. The percent by species

   , collected             by     electrofishing       is      fairly     consistant (Figure 14), although the black crappie population appears to be decreasing slightly over time.                   The percent of "other sunfish",            excluding     bicegill,    seems     to   be   increasing,
                          ,                                g             __n          -               ~

n __ Figure 12. ~ ~ - V J. v __ __ u q-- , ..

n. -. _

qn ._g..., ,

                                                                                                                                        \
                                          --               s              .        -  .-                        'J..--                    1
                                                                                                                                               .-               sa               -

s .a 1 _ a( e A n n a , .' ~C R_ ~C R_ B _ CPlJ 140 -- --+ -- - - - - - - -- -- - - -- -- - - -- --- - 120 - - - - - - - - - - - - - - - -- - -- -- - 100 - - - - - - - - -- -- - - - - -- -- - - - - - gg _. .. . .N . . .. . .. .. .. . . .. . . .. .. .. 60 -- - -- -- - - ------- -- - - - - - - - - - - 40 - --

                                   =
                                                                                                                                                                                                        /

20 81 82 83 84 85 85 87 88 Years Sill. NET  : ELECTRFISH 3m a mm W mW W W W W W M M M W . W W E

h L_J U L ~> Figure 13. l l Lake Anna Fisheries Lake Anna Fisheries Total Number Comparisons Total Weight Comparisons . l

                 ^

EGD4D

                                                                      "                                            EGEND
   -.                                                           ..                                                 Mi l

U sen7 ***' ' 5 soni E i. U i. , am- - m. see.. page. . 3 Totof Wefght Total Number Lake Anno Fis h e r-l e s Species and Fa mily C o m p a ris o n s

                   "                                                                                   LEGEND M     2...

E toes p..

                    ?

FF penantam FF Femmittam ON menetem ON Fa mff tem

1

                                                                                            --                                r .

Figurd 14. [ L [3

                                                       \s            A  1 I    L 3.'~ ~7[~~~Q s s         .       -w         ..U.

f.E83-:.E88, Percen: 0" ~otal Ca cl i percent 100 80 1 1 l 60 - - - y _................................ ............................................................. g ............... ............... b O m largenouthbass bluegill J othersunfish mm,J black crapple Ester 136 l kight1985 E Mater 1987 hight 1967 M mater ines -+- thight ins

perhaps to fill the niche vacated by the black crappie (Figure 15). The gill net comparisons-(Figure 16) demonstr-ate greater yectly fluctuations in individual species for reasons discussed earlier. The only obvious trend is, again, a consistent decline in the proportion that black crappie comprises of the total catch. Past studies have noted the decline of black crappie in the lake (Virginia Power, 1983 and 1986) and hypothesized a lack of sufficient shoreline structure as a possible cause. This was one of the primary reasons for the construction of artificial fish structures in the lake. As of December 1988, seven artificial fish structures have been added to

m the original seven fish structures installed in Lake Anna by g

l the close of the North Anna 316(a) study. Six of the seven I g fish structures installed since 1985 were constructed of 1.000 to 1,700 cinderblocks and eight hardwood treetops each. One fish structure consisting of four separate piles of 425 block and 4-9 hardwood treetops was constructed within casting distance of shoreline fishermen at Dike 3.

            ^

Construction of four additional fish structures is planned l for the spring of 1989. In 1988 a monitoring program for the fish structures was initiated with the purposes of assessing the effective-ness and longevity of construction materials and examining ( fish utilization patterns. A series of SCUBA dives was made on five fish structures during the period August-October g 1988. Divers made. replicate counts of fish on each dive, noting habitat use and the condition of construction I - - . -

I i na-e is. Electrofish Results ' Lake Anna Reservoir, 1986-1988

                                                    % by number                                                                     ,

I LEGEND LEGEND M L macrochirus 71.8% L macrochirus 68.7% ! M M. so!moldes 5.8% M M. solmoides 8.5% M L ouritus 1.9% L ouritus 3.5% M L microlophus 2.3% M L microlophus 4% M P. nigromoculatus 11.7% M P. nigromoculatus 5.3' ! 4 L gulosus 2.4% M L gutesus 2.4% other 4.1% d other 7.6% 1986 198/ i \ )

LEGEND L macrochirus 72.6%

i M M. so^moldes 7.1% L ouritus 6.5% M L microtophus 5.1% f M P. c.v c,.T.c,culatus 3.7% f . M L gulosus 2.6% l d other 2.4% \

                                                 ~1988 as a          m     a   a   e        e         m        M   M   W       W         M        M M     M        M      M     M

MMMM1 aus as aus en sua sans aus ama aus seum ens M m aus aus sum num num amm l n'- - Figure 16. e 3 - e 1 3 .

                                           -L.        J                L        J        .  . .   .       s    a
                                                                                        .       = =        .

L8mrL88, ercen: o~ 0:a.. q2:c1 1 percent 30 3 _.................................................................................................................. 3 _...................................... 1 ns l l P 10

                                 -*~m-                                   --                --
                                                                                                        -- - -// -- ---- -- -               -

J 5 0 largenouthbass malleye stripedbass blackcrappie

                   =

haber 195 M might ins + maberim R 2 m ight im 7

               - * - msber !m e              M might 1918

- 1

I materials. Preliminary results indicate that since 1981 most construction materials have maintained their integrity, with conifers becoming more attractive to fish after the needles decomposed. In general, bluegill occupied submerged conifers largemouth bass, hardwood treetops and channel catfish, l cinderblock, Black crappie most frequently utilized the densest woody cover available or stayed suspended above the fish structures. Recommenda' c ions for the study period 1989-1991 include: 1. Continue quarterly gill net sampling of the lake and I WTF at the six historical stations. 2, Continue quarterly electrofish sampling of the lake and , WTF at the nine historical stations, a 5

3. Continue cove rotenone studies in conj unction with l

representatives of the Virginia Department of Game and Inland Fisheries as per their schedule--presumably every three years. 4 Continue to monitor and maintain the artificial fish structures in Lake Anna. I I E

l 4,4 Lartemouth Bass Age and Growth Lake Anna supports a prominent and economically important largemou h bass population. Studies have been I condacted for several years providing a substantial data base for characteriting the age and growth parameters of Lake Anna largemouth bass. The largemouth bass collected in this study period, 1986-88, were measured for total length to the nearest mm, weighed to the nearest gram. Scales were also removed for age determination. Back-calculated lengths for each age were determined using the method described in Everhart and Youngs (1981) and mean lengths for each age group

                                                                                                                                                         .e compared to the Virginia state average growth of largemouth bass from Virginia reservoirs (Smith & Kauffman, 1982),

Results from the follow-up study were compared by year of collection and then combined for comparison to data presented during the 316(a) demonstration. During 1988, a total of 85 largemouth bass were collected from Lake Anna and the WHTF for age and growth determinations. Collections in the lake yielded 58 specimens representing four age groups and collections in the WHTF yielded 25 specimens representing two age groups (Table 6). Growth of largemouth bass from both the lake and

                                ,the WHTF exceeded the Virginia state average for reservoirs.

In fact, throughout the course of the follow-up study, mean lengths consistently exceeded state averages (Tables 7 and 8). Weighted mean lengths calculated for all largemouth

I Table 6, Mean backcalculated lengths of largmouth bass collected fmn Lake Anna and the WIT during 1988. l I

                                                   ,                          I 1              2           3             4 Mean Imgth                      147            248         356 I

408 (n) (58) (38) (10) (6) (Range) (231-85) (324-193) (464-301) (456-352) Increment 147 101 108 52 I 3 Mean Imgth 180 284 (n) (25) (19) I (Range) (255-95) (359-213) Increment 180 104 I VA State i Mean lagth 124 246 328 378 Increment 124 122 82 50 g I I a.,

E I ~ Table 7. Wtan backcalculated ler of largecruth bass collected in Lake Ama from 1986 to 988. A2 1 2 3 4 5 6 7 8 9 5 1986 143 255 353 422 470 509 51 9 543 560 (n) (56) (34) (22) (12) (9) (5) (3) (1) (1) I 1987 134 258 333 407 454 477 (n) (42) (39) (18) (16) (6) (1) 's 1988 147 248 356 408 (n) (58) (39) (10) (6) I VA State it (1981) 124 246 328 378 434 462 508 564 559 I I I . I I I -

I I Table 8 Mean backcalculated length of largecouth bass collected in the IMIT, VA frcm 1986 to 1988. I 1 2 3 4 5 6 7 I 1986 171 294 362 442 (n) (39) (24) (6) (1) 1987 160 264 323 371 477 496 515 (n) (36) (31) (11) (!*) (1) (1) (1) 1988 180 284 (n) (25) (19) VA State i 124 246 328 378 434 462 508 I I I

                                                                    ~

I l I e

i. n
                                               ,  --    . . . - - - - , - ~ - - . . , . . . - , - , , , . .   --

i bass collected during the follow-up study compared favorably I *o means present in the 316(a) demonstration (Figures 17 and 18). Lake Anna supports a popular sports fishery and has l consistently produced large numbers of citation-size fish (over 8 pounds). Historically, Lake Anna has ranked among the top producers of citation largemouth bass in the state. Over the course of the follow-up study, Lake Anna led the state two years and placed third in 1988 for the greatest number of citations awarded this species. K-factors (condition factors) of fish from both the lake and the WTF were comparable to those reported in other systems (Carlander, 1977). K-factors greater than one generally indicate a healthy population. Mean K-factors for all age groups collected during 1987 and 1988 were greater than one in Lake Anna (Table 9). The increase in K-factors with age that was observed is common in largemouth bass populations. In general, largemouth bass from the WTF exhibited greater K-factors than those from the lake. The data from the lake and the WTF indicate both systems support healthy largemouth bass populations exhibiting growth rates exceeding the Virginia state averages. Over the course of the 316(a) study and in subsequent years, the populations have experienced drought conditions and periods of high power station output. p Despite these conditions, both the 1.ake and the WTF popu-7 lations have displayed consistent growth rates. Over ten

mt . Figure 77 Mean growth eterves of largemouth boss collected in Lake Anna VA from 1978 to 1988. eco - - LEGEND

                                                                        .. 3'r                    1978-1985*

j X ,

             ,ao.  -
                                                          -G*-

__ 1986-1988.*

                                                       /     .-
                                                     /
                                                   !                                     ....... VA state M ea n + + +

j 400-  !,~~

                                           / .. -

n / E ,[.' a y 300-- /,.~/ t a j.- 200--

                           /
                         /
                       /

100--

                                                                   ^     ^

O - + - - 1 2 3 4 5 6 7 8 9 age

                         -
  • VirgInfo Power. 1986 ** Weighted mean +++ Smith and Kouffmon, 1981 M ME W W M M M M M M M M M CM M M M M M

Figure 18 Moon growth curves of largemouth boss collected in the North Anna WHTF. VA from 1978 to 1988. 600-- 1978-1985

  • 50 -- 'C~ _ ___ 1986-1988 **

f

                                                                                         ...... . VA State    ***
                                                   / *
                                                ,/

l 400-- m / E .#  !' E # h ]soo-- /..f ' s - 5 l. 200-' -

                  /

100-- 0-- - 1 2 3 4 5 6 7 oge

                                                        .. Weighted moon   ... Smith and Kouffman, 1981
  • VIrginio Power, 1986

I I Table 9. Mean K-factors for largamuth bass collected frcxn Lake Arne and the WIT, VA during 1987 and 1988. E 5 I

                                            =

1 2 3 4 5 6 7 I the 1987 1.1 1988 1.1 1.2 1.2 1.3 1.4 1.6 1.5 1.7 1.9 l I g 1987 1.2 1.2 1.5 1.2 -- -- 1.7 1988 1.5 1.2 I E I E I I I I,

                                                                              .E

l years of age and growth data have been recorded for large-mouth bass in the lake and WHTF providing a substantial data base with which the populations have been characterized. l Reconnendations for age and growth for the study period 1989-1991 include

1. Largemouth bass collected during routine sampling, i.e., electrofish, gill net and rotenone, will be utilized in an ongoing age and growth study. Pooled results will be reported every third year.

4.5 Striped Bass Studies The 1986 316(a) demonstration for the North Anna Power Station reported the findings for striped bass studies during the period 1981-1985. Subsequent to the conclusion of the 316(a) study, the Company agreed to continue studies of the lake's striped bass for three years, at which time the need for further studies would be determined. Results of the 1986-1988 studies indicate the condition of the Lake Anna striped bass fishery has not changed significantly since studies began in 1981: therefore a reduced monitoring program is reconnended. Striped bass were introduced into Lake Anna by the Virginia Commission of Game and Inland Fisheries in 1973 and have been stocked annually since 1975. Since this time, summer habitat conditions for striped bass in Lake Anna have '

I been determined to be "sub-optimal" duc to the

 " thermal refuges" with temperatures below 75'C and dissolved lack of l

oxygtn concentrations above 2 ppm. Striped bass s tud'.e s repotted in the 316(a) demonstration indicated summer habitat conditions were temporarily checking growth of Lake Anna striped bass resulting in smaller fish, relative to age g group, compared to the average for Virginia reservoirt.. The 1986-1988 study results indicate the effects of :he sucuner checking of striped bass growth may not be as severe as previously indicated in the 316(a) study and that the growth of striped bass in Lake Anna is equal to or better than the Virginia State average. A total of 333 striped bass were collected during the peciod 1986-1988. Scales were collected from the fish for age and growth studies in the area boundei by one scale row below the lateral line and anterior of the tip of the pectoral fin when it was laid flat along this scale row. Additionclly, otoliths were collected from 98 of the larger striped bass for verification of scale analyses. The age group of each fish was determined from the l scale data with the method proposed by Hile (1941), Body length of each fish at time of annulus formation was back calcul.sted using the formula of Everhart and Youngs (1981) with a standard intercept of 35 mm (Virginia Power 1986). Mean lengths for each age group were compared to the g Virginia state average and previous Lake Anna age and growth analyses. These analyses were repeated using the otolith data. Results from the two daca sets were compared to

c L - F L determine if chey were significantly different. Means were c orapare d using the Wilcoxin-Mann-Whitney nonparametric t ~ C when test, sufficient data were availab',c, as the { Kolomogorov D and Shapiro-Wilk W statistics for age 1 - age s 6 data indicated the majority of the data to be non norrally distributed (2ar 1984). Small H values for fish collected above age 6 precluded their use in the above analyses. Mean lengths esiculated from the 1988 scale data (Figure 19) follow the trend reported for the 1986 and 1987 collections (Virginia Power 1987, 1988). Mean length data from the 1986-1988 (post 316(a)) collections were combined for subsequent comparisons to reduce the effect of year class variability. Statistical comparison of post 316(a) mean lengths to means for Virginia reservoirs (Smith and Kaufman 1982), was limited to graphical assessment of confidence interval overlap as insufficient data was available for the Virginia data set to perform I, tests. The overlapping confidence intervals suggest the Lake Anna mean lengths, as determined from the scale data, are not cignificantly dif ferent from the state average for any age group (Figure 20). Mean lengths deternined from the post 316(a) otolith data howe're r , r- significantly larg.ar (e 0.05) than the, means determined from the scale da t.a for age groups 1-3 (Table 10) and demonstrate the growth of age group 3 1-2 to be significantly better Aan the Virginia average (Figure 21). _ _ - _ _ - - . - - - - - ' i -__ _ _ - - _ - --- -

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I l~ Table 10. Significance of differences between scale and otolith mean lengths.*

   ]

I _ Ace Group Level of Significag e I 1 0.0001 0.0001 2 3 0.0025 4 0.6521 5 0.2983 6 0.3519 I I

  • Mann-Wittney comparisons I

Comparison of the post 316(a) scale data to the 1981-1985 316(a) scale data demonstrate the post 316(a) mean lengths to be significantly larger (4 - 0.05) for age group 1-4 (Table 11). Comparison of the 316(a) otolith data and 316(a) scale data was not meaning;ful due to the scall number of oteliths availabic for the 316(a) data set, l The growth trend for the post 316(a) collections does not reflect the trend for the 316(a) collections, possibly due to differences in the methods used to analyze scales during the 316(a) and post 316(a) studies. Striped bass g scale analyses are prone to overestimating age and under-estimating length because of the presence of false annuli. The 316(a) study indicated that Lake Anna striped bass may l be laying down false annu11 during spawning periods and during a summer period of reduced growth. Post 316(a) scale analyses attempted to discern real and false annuli by correlating scale corphometrics with periods of spawning and/or summer stress. Studies by Pikitch and Heidinger and Clodfelter Demory (1988), Sharp (1987), O'Gorman et al. and Bernard (1988), (1987), l Carlander (1977), and others have indicated that age and mean length determinations from otolith data are more accurate than those from scale data for a variety of marine and freshwater fish. Accordingly, post 316(a) scale data vere compared to the otolith data to assess the accuracy of l the analyses. The results indicated the post 316(a) scale analyses had good success in determining accurate mean lengths for age groups above age 3 and diminishing success B M

il l Table 11. Significance of differences between 316(a) and l post 316(a) mean lengths.* i ) Age Group Level of Sienificat.cc {I I

I 0.0001 i

. 2 0.0001 l 3 0.0001 1 i 4

                                                                                   )

4 0.0001 1 5 0.0653 i ! 6 0.2924 1 i lI i

  • Mann-Whitney test of scale data

.il !I lI I I 53-

I I with age groups 1-3. These results suggest the post 316(a) scale data underestimates the lengths of younger striped bass and that the post 316(a) growth trend is therefore a conservative indicatri of striped bass growth in Lake Anna. Although the post 316(a) scale and otolith analyses indicate growth since 1986 has been equal to or better than the state average, it fails to indicate whether the increase in growth from 316(a) Icvels is due to a change in the condition of the fishery or a change in scele analysis methods. An attempt was made to address this que s tion b,' using a comparison of 316(a) and peut 316(a) length frequency distributions, as measurc.ments of fish lengths are not as prone to the subjective sourcos of error as ocale and otolith measurements are. Ideally, isngth frequency distributions will show distinct groupings of lengths that correspond to the age groups in the sample population: however, this is seldom seen outside of the younger age E 5 groups as genetic, environmental and other factors increase the variability of growth within older age groups. To minimize length variability introduced by across-season sampling, the sample population was taken from as narrow a sample period as possible which would still adequate number of fish for the analyses. contain an The optimal l sample period was ascertained to be the months of February, March, April, and May. A comparison of the 316(a) and post 316 ( a'e length frequency histograms was made by dividing the histograms into the "most apparent" length clusters (Figure 22) and 5l

ll Figure 22. g Length frequency distribution of 316(a S post 316 a striped bass collections. l wngth imauency D - I 6 - < < < I a . , h 2 - < ' < ' I o 200 400 600

                                                                                                                                                   -A 800 lergth (mm) 316 a I

I len gth frequency

           'o g                    =...                                    ...                                                 ...                    ...                     ...            ,,,

B - 6 - A 1 2 - , O - - - - - - - - - - - - - - - I 200 400 lengih (min) 000 eco g post 316 a, I -

( comparing the these I means of clusters. The analyses indiested: 1) the distribution of the 316(a) and post I 316(a) length clusters is approximately the same, 2) Post 316(a) and 316(a) cluster means are similar (Table 12) to one another and to the means of the post 316(a) scale / otolith analyses. These sicilarities suggest that the l lengths attained by the taspective age groups have not changed significantly from 1981 to the present and that the growth rate of Lake Anna's striped bass fishery is equal to or better than the average for Virginia reservoirs. Condition Factors and Habitat Availability Studies of striped bass condition and habitat availability continued in 1988. Average condition factors for striped bass collected from 1986-1988 are presented in Figure 23 by quarter and age group. The data indicate an apparent decrease in condition during the summer months k which correlates with a reduction in preferred habitat for $ striped bass (Figure 24). This has been the prevailing trend since Lake Anna striped bass studies began (Virginia Power 1986) due to the development of an anoxic hypolimnion during most summers in water deeper than 12-13 meters. The warmer epilimnion varies in dissolved oxygen concentration from 2-8 ppm. The return of striped bass condition factors to normal values ( 1.0) early in the year also follows the trends of past years. The number of citation striped bass ( 15 pounds) reported for Lake Anna in 1988 was about the same as the number reported in 1987 (Table 13). I

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i j Table 12, Mean lengths #or cluster groups in leitsth f requency analyscs. !I 81-85: Ace / Mean 86-88: Age / Mean i;

;                                                                    1 / 268 m                             1 / 286 mm
;                                                                    2 / 388 m                            2 / 423 m 3 / 517 m                            3 / 510 c:m 4 / 597 cm                            4 / 587 ::m 5 / 692 m                             5/702c:m                                                              l 6 / 794 mm                            6 / 795 cun ll
.I                                                                                                                                                                              i 1

l 1 1 I i 1 1 I _. _ _ _ _ -.. _.-___ _-__._. _ ._ _ _ _ , . _ . _ _ - - _ _ __ _ _ _ _ . _ _ . _ .._.. _ _.

i I l l Table 13. Number of citation bass (>/= 15 lbs) caught from i Lake Anna.* l i j I Year Citations i 1979 5 l 1980 10 1981 42 E 1982 60 19e3 53 1 . 1984 $7 1986 19 E Ii 1987 31 1988 29 l 1 , * (Virginia Game and Inland Fisheries) I I E_

                                                                          .AA.

P Conclusions e The extensive data collections and analyses made on the k striped bass of Lake Anna have indicated that the lake f supports a productive striped bass fishery that has growth rates similar to the Virginia state average, despite the presence of a short summer period of habitat reduction. Recommendations for the study period 1989-1991 includei

1. Striped bass collected during routine sampling, electrofish, gill net and rotenone, will be utilized in h an ongoing life history study. Pooled results are to be reported every third year.
2. Summer habitat surveys will be continued during peak summer months monitored by quarcerly plume surveys which are sufficient to determine any changes in the amount of habitat available.

I 4.6 Lake Fish Summary The 1988 fish collections from Lake Anna and the subsequent analyses are remarkably similar to data collected from previous years. There has been little change in the forage and gace fish popul : ions during the threeg est study period. Age and growth studies of largan', .h bass and striped bass indicate growth rates en2sistent with past years and which compare favorably to growth rates from other

g; areas of the state. Overall the results of the three-year fish study indicate that Lake Anna contains a healthy, diverst, well-balanced cocnunity which has changed little since the 316(a) study, I t 5 1 I E 5 E t I l . 1 I E

                                                                                      -62
                =

l 5.0 Macrobenthos Benthic collections were continued during 1988 to monitor the population of Asiatic clams Corbicula fluminea in Lake Anna. Corbicula have the potential of infesting and fouling condenser tubes thereby reducing water flow and i power station efficiency. This problem has not been encountered to date at the North Anna Power Station. Collections were made during April, July and September at two stations in the lake (mid and lower lake) and two stations in the WTF (WTF 1 and WTF 3) using an Ekman i t dredge. For each station a collection consisted of three replicate samples composed of one grab each. Corbicula were sorted into four size classes and counted. Values presented in thia report are totals of all size classes and all replicate samples for a given collection. Data collected during 1988 was compar ed to collections made during the follow-up study and to data presented in the 316(a). In 1984 and 1985, five replicates were collected rather than threes therefore, those data have been adjusted to be consistent with collections made using three replicate samples. Some comparisons consider only Corbicula larger than size class 1. Prior to 1986, specimens were not sorted by sizes therefore, comparisons regarding size classes are restricted to collections made during the follow-up study

  • period.

Corbicula were present in all samples collected during 1988 (Table 14). Trends described by these data were I I Table 14 I Corbicula fitz:dnea collected in D=an dredge samples fmn Lake Anna rad the WIT, VA durir4 1988. I me - -- -1 .3 I sz - 22 m 18 1, 3 Sat'ER 32 182 492 59 g N ._5 J_32 26 g N ML M AL 59 535 536 90 I i E I t i E l I I E

consistent with collections made during the follow-up study and during the 316(a) demonstration (Table 15). The his-toric spatial trend in which the mid-lake produced greater numbers of Corbicula than the lower lake continued during 1988. The month during which Corbicula densities peaked varied however, minimum values occurred during September at both stations. Corbicula densities in the WTF were higher in WTF 1 than in WTF 3 and peaked at both stations during Ie July. In most collections, size class 1 organisms ( 7.5 mm) dominated the samples and the majority of those were sand-sized organisms. While numbers of size class 1 organisms appear to have increased in recent years at some stations, there appears to be little correlation between the number of size class I clams at a station during one year and the number of clams size class 2 or greater present during successive years. The occurrence of these sand-sized organisms causes a large degree of variability between samples. Numbers are more consistent when only Corbicula greater than size class 1 are considered (Table 16). Recommendations for the study period 1989-1991:

1. Discontinue Corbicula sampling since the adult Corbicula population has remained relatively stable historically and the presence of Corbicula in the system has not impeded the operation of the power station.

I - _ _

I Table 15. corbicula fluminea collected in Denn dredce saaples from lake Anna and r3w WIT, VA. Values are totals of three replicate samples.

  • tb sa ple taken.

I 1984 1985 9 1_9!,6, 1987 1988 imer 1.ake Spring 40 66

  • 17 22 Sunner 19 15 33 9 32 Fall 7 31 9 11 5 Annual Totals 66 112 42 37 59 Mid-143 Spring 65 146
  • 23 221 Sutter 35 67 32 19 182 Fall 65 64 178 920 132 Annual Totals 165 277 210 962 535 MUT 1 Spring 12 59
  • 26 18 Sucner 15 0 0 104 492 Fall 7 9 69 61 26 Annual Totals 34 68 69 191 536 MnT 3 l

Spring 32 70

  • 22 1.1 Succer l

45 45 26 17 59 Fall 36 60 39 29 12 Annual Totals 113 175 65 I Ge 90 g 3 i I l Table 16. Corbicula fite:inea larger than size class 1 0>7.5ce) present in collections irco L9ke Anna and the WrF. * !Ls sepla taken. 1 1986 1987 1988 Imer IAe Spring

  • 5 7 Strcer 16 7 2 Fall 7 4 4 Total 23 16 13 Mid-Lake Spring
  • 9 8 Storer 13 6 5 Fall 16 5 3 Total 29 20 16 WrF 1 Spring
  • 0 1 Struer 0 2 2 Fall 1 5 5 Total 1 7 8 1

WTF 3 Spring

  • 21 9 Stecer 20 17 11 Fall, 39 29 3 Total 59 67 23 1

l . . . .

I E 6.0 Chlorochv11 (a) Sampling for chlorophyll (a) was continued during 1988 in Lake Anna as a means of determining trends in the phyto-plankton population. Results of the 316(a) demonstration of the system indicated spatial and temporal trends in chloro-phyll (a) concentration paralleling trends in phytoplankten density and biomass which can therefore be used to describe changes in the phytoplankton population (Virginia Power, 1986). The 1988 results were compared to other data col-1ected during the three-year followup study to the 316 (a) demonstration as well as to selected data collected during the 316 (a) demonstration. Sampling locations and methodology were consistent with those employed in 1987. Monthly collections were made in the upper lake (Rt. 208 bridge), mid-lake (ENDECO buoy at power station intake), lower lake (boat blockade in front of the dam). WTF 1 and WTF 3. Each sample consisted of two liters of water preserved in the field with 1 ml MgC0 3 per liter sample. Chlorophyll (a) concentrations were determined by Virginia Power's System Laboratory. Mean chlorophyll (a) values were derived from two surface and two four-meter replicate samples collected from each station. Chlorophyll (a) l concentrations were calculated using the formula presented in Virginia Power, 1986 Calculations

   = occasionally yielded negative values which were considered to be zero when calculated in means, a

_B [ Mean chlorophyll (a) values peaked in the upper lake during January at 9.7 mg/m3 and in the lower lake during July at 1.8 mg/m3 (Table 17). Values at the mid-lake station peaked during February at 3.4 mg/m). Minimum values occurred during May at all stations and ranged fw 1.2 mg/m3 d.n the upper lake to 0.6 mg/m3 at the dam. l Spatial patterns of chlorcphyll (a) concentrations have historically described a decreasing gradient from the upper lake to the dam continued in 1988 (Table 18). Seasonal patterns of chlorophyll (a) concentrations at the upper lake station were similar in 1988 to those observed during 1987 ( with peaks early in the year and during the summer (Figure 25). This pattern is typical of impoundments in this geographical region with the separate peaks due to different Mgal groups that flourish under specific I environmental conditions (Wetzel, 1985). According to Wetzel (1985) diatoms flourish in the colder months of winter and early spring whereas blue-green algae dominate in l warmer conditions of s utame r . These patterns can be disrupted when the environment is disturbed by external influences. Chlorophyll (a) concentrations in the lower lake and the WHTF during 1987 and 1988 were variable and lacked a winter / spring peak, possibly due to the thermal effluent which may alter the typical seasonal pattern

   - (Figures 25 and 26).

Secchi depth measurements were taken in conj unction with chlorophyll (a) surveys during 1988 to determine their agreement with chlorophyll (a) concentrations and thereby

                     -    _ _ _ _ - _ _ _ ______I  !I                        - - - - - - - -

Figure 25. Chlorophyll a concentrations from three stations in I.a k e Anna. Virginia. a

                   "                                                                                               LEGEND upper  '
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                                              .                                                                                                                                                                     l Table 17   ltan chicrophyll (a) values (cg/m3) irce Lake Ama, VA during 1988.

Ottns of 2 surface and 2 4m reps.) m [ E Station l 208 Month Bridge Intake Dam MirF 1 MUT 3 1 9.7 1.7 1.5 1.9 0.9  ! 2 9.0 3.4 1.0 2.2 0.8 3 5.8 2.0 1.7 1.8 1.5 4 2.8 2.5 1.6 1.8 1.1 5 1.2 1.1 0.6 0.6 0.7 6 g 3.0 1.2 1.4 1.3 0.8 7 5.9 2.4 1.8 2.6 *1.1 8 6.1 1.4 1.4 2.3 1.1 9 3.0 1.5 1.2 2.3 1.1 10 1.6 1.7 1.2 1.1 1.1 a 11 2.7 1.6 1.2 1.4 1.3 12 2.3 1.4 0.4 1.1 0.8 I a 8 E I

                                                                                                                                         ~ -    _         _ . - . . _ . . _ . . . - . _ _ - _ . . - _ . - _ _ _ . - _ _ . . - - _ . - _ _ . - _ _ _ . _ . _                    .--_ _ _ . . . _ . _ . . . _ . _

1---- _ Table 18. Mean chlorophyt t (a) vatwes (og/m )3 f rom Lebe Anna and the WHTF, VA, frese 1985 to 1988. (Valves are mean of two surf ace and two four-meter replicate samples.) *Mo sagte taken. t Rt. 208 Pridge intabe Das witF 1 WTF 2 Month 1985 1986 1987 1988 1985 1986 1987 1958 1985 1986 1987 1988 1985 1986 1987 1958 19R5 1986 1987 1789 . Jan. 15.6

  • 7.4 9.7 1.9
  • 1.2 1.7 0.7
  • 1.0 1.5 1.2
  • t.0 1.9 1.0
  • 0.8 0.9
  • 2.2 3.4 + 1.1 Fete. 17.1
  • to.4 9.0 2.3
  • 1.9 3.4 3.6
  • 1.3 1.0 3.4 2.6 0.8
  • 2.4 1.8 7.3 + 2.1 Mar. 21.0
  • 5.9 5.9 7.9
  • 2.5 2.0 6.4
  • 1.1 1.7 4.5 1.5 e
  • 1.7 1.8
  • 1.1 1.1 Apr. 4.2
  • 2.6 2.8 3.3
  • 0.8 2.5 2.2
  • 1.1 1.6 3.4 3.0 5.5
  • 1.1 1.2 4.3
  • 1.1 1.1 1.8
  • t.3 0.6 2.5
  • 1.1 0.6 2.0
  • 1.5 0.7 May
  • 3.0 2.7
  • 3.6 1.2 1.6
  • 3.1 1.4 1.9
  • 1.9 1.3 1.7
  • 1.5 0.8 I J n. 5.0 3.1 4.3 4.1 4.3 5.9 2.8 1.8 1.3 2.4 17 2.0 4.1 1.8 1.8 1.9 3.2 2.6 - 1.7 6.4 f.1 Jul.

3.1 6.4 6.1 2.7 2.1 2.4 I.2 1.6 1.0 1.2 1.4 3.4 2.1 2.1 1.6 1.7 1.5 1.3 1.1 , Aug. 4.8 3.2 5.9 3.0 2.2 4.1 1.5 1.5 2.1 1.8 1.2 3.1 3.1 3.2 2.3 1.5 2.1 2.2 1.1 Sep. 6.1 4.8 4.1 1.6 1.5 8.7 1.9 1.4 1.0 1.2 2.2 1.5 1.8 1.1 2.0 0.9 1.1 1.1 Oct. 3.8 3.7 2.0 2.5 2.2 6.3 2.7 2.7 1.8 1.4 1.6 1.1 2.6 0.8 1.2 1.5 1.9 1.4 1.4 0.4 1.2 0.8 1.3 Nov. 3.7 4.3 4.2 6.5 2.3 0.5 1.6 2.3 1.4 0.4 1.9 1.1 0.4 0.1 1.5 2.4 1.1 0.8 1.t 1.6 c.8 Dec.

serve to predict phytoplankton trends. The assumption was that Secchi depth is inversely related to chlorophyll (a) concentration, i.e. the shallower the Secchi depth (greater trrb'iity), the greater the phytoplankton and nutrient t density (Table 19). With the exception of the November , measurement, secchi depths were the least in the upper lake where chlorophyll (a) concentrations were highest. This hypothesis did not hold true further dcwn the lake as five 4 montha out of the year secchi depths were greater at the intake station than the dam, while the chlorophyll (a) concentrations during those saca months were greater ..- *he . intake station than at the dam. 7 Chlorophyll (a) concentrations have been moni. td f r several years in Lake Anna. The results of these at d achi r historical data (phytoplankton, nutrients, periphyta) indicate that although monthly results may vary, generai 9 ~

f. trends within the system have remained consistent and no g 6 >

j deleterious effects have been identified. Lake Anna is a thriving system with ample productivity at the primary level to support upper trophic levels. Recommendation for the study period 1989-1991:

1. Discontinue chlorophyll (a) sampling since a database currently exists that is sufficient to characterize the system. This extensive database indicates primt.ry g productivity in Luke Anna for both pre-operational and post-operational conditions is similar and sufficient to support upper trophic levels.  ;
                                                                                .a,!

fable 19. Chlorophyll (a) ?n the phytoplankton at t ake Am. , VA, during 1988. T he vnits are milligrams / cubic meter. The secchi deptb (H) is also presented. Negative volumes are cor+sideteo 3 in ralculation of eeans. R1, 209 Rt. 108 DAM PfPTH RfP9ICAff BRIDCT INTAkf5 DAM OfPTH REPLICATE BW 74E INIAkf5 DAlf: JUl Y DAlf: JANUARY 4.70 Secchl Depth 2.60 3.10 3.00 Seccht Depth 1.70 3.50 1.67 1.80 Chlorophyll (a) 0 1 5.34 2.14 1.78 Chlorophyll is) 0 1 9.89 4.40 1.78 1.67 Chlorophyll {a) 0 2 10.37 2,07 1.5% Chlorophyll (a) 0 2 1.47 1.40 Chlor ophyll (a) 4 1 6.94 3.20 1.87 Chlorophyll (a) 4 1 9.71 6.76 2.35 1.87 Chlorophyll (a) 4 2 8.62 1.74 1.34 Chlorophyll (4) 4 2 1.52 Hean 5.86 2.37 1.80 Hean 9.65 9.74 , DATE: AUGir5T DATE. [EBRUA9; 3.33 Seccht Depth 1.30 2.00 2.30 Seccht Depth 1.25 3.40 0.93 Chlorophyll (a) 0 1 6.00 1.82 1.17 Chlorophyll (a) 0 l 13.17 4.87 1.28 4.60 1.00 Chlorophyll (a) 0 2 5.81 1.94 Chlorophyll (a) 0 1 13.14 -0.64 1.82 Chlorophyll (a) 4 1 4.14 1.94 1.13 Chlorophyil (a) 4 1 6.10 1.00 Chlorophyll (a) 4 2 5.72 1.82 1.39 Chlorophyll (a) 4 2 4.77 2.05 3.36 1.02 Hean 6.06 1.40 1,42 Hean 8.98 DATE: STPifMBER DATE: MARCl3 3.00 Seccht Depth 2.85 3.40 3.75 Seccht Depth 2.50 2.50 Chlorophyll (a? O 1 0.69 1.96 1.07 Chlorophyll (a) 0 1 6.30 1.94 1.67 1.42 2.27 1.54 Chlorophyll (a) 0 2 2.97 1.42 Chlorophyll (a) 0 2 5.34 3.96 0.36 1.42 Chlorophyll (a) 4 1 5.74 1.80 1.74 Chlorophyll (a) 4 1 5.74 2.14 1.67 Chlorophyll (a) 4 2 3.96 2.31 0.89 Chlorophyll (a) 4 2 1.65 Hean 2.89 1.51 1.20 Hean 5.78 2.0% DAIE: OCTO6fR DATE: APRIL 3.13 Secch! Depth 2.90 2.90 2.90 Secchi Depth 2.40 3.00 1.?4 Chlorophyll (a) 0 1 1.78 1.51 1.16 Chlorophyll (a) 0 1 2.58 2.35 1.42 2.18 1.47 Chlorophyll (a) 0 2 1.69 1.78 Chlorophyll (a) 0 2 2.49 1.34 1.69 0.98 1.94 Chiorophyll fa) 4 1 Chlorophyll (a) 4 1 3.20 2.54 1.60 1.34 3.07 1.74 Chlorophyll (a) 4 2 1.51 Chlorophyll (a) 4 2 2.85 1.62 Hean 1.58 1.65 1.22 Heen 2.78 2.53 DATE: Pt4y DATE: NovtHHi rt 3.00 Secchi Depth 3.50 3.40 3.70 Seccht Depth 3.00 3.00 0.53 Chlorophyll la) 0 1 1.23 1.34 1.07 Chlorophyll (a) 0 1 0.73 1.18 1.34 1.27 0.73 0.94 0.53 Chlorophyll la) 0 2 2.40 Chlorophyll (a) 0 2 0.73 Chlorophyll (a) 4 1 3.20 2.07 1.70 Chlorophyll (a) 4 1 1.74 1.00 1.20 1.67 1.34 0.53 Chlorophyll (a) 4 2 2.85 1.54 Chlorophyll (a) 4 2 1.22 1.11 0.58 Hean 2.67 1.57 f.18 Hean DATE: DECEMBER DATE: J'JHE 3.40 3.25 Secchi Depth 2.90 3.30 3.80 Secchl Depth 2.70 1.13 1.07 Chlorophyll (a) 0 1 2.05 1.34 0.80 Chlorophyll (a) 0 1 1.28 1.40 0.73 2.24 1.20 1.07 Chlorophyll (a) 0 2 2.31 Chlorophyll (a) 0 2 1.30 Chlorophyll (a) 4 1 2.23 1.54 -1.07 Chlorophyll (a) 4 1 5.98 0.98 2.58 1.47 1.00 2.35 1.34 2.06 Chlorophyll (a) 4 2 Chlorophyll (a) 4 2 0.61 1.37 Hean 2.29 1.44 Hecn 2.96 1.16

1 Nort'.1 Anna River Biota of the North Anna River below Lake Anna have been sampled extensively since the lake was impounded in 1972, with pre-impoundment studies dating to 1971 (Virginia Power, 1976). With the acceptance of the findings from the 316(a) study, the WCB also approved a three-year reduced study plan for the North Inna River, below the dam, which has been followed from 1986 through 1988. This section summari::e s the 1988 results of the study and compares these results with the prior two years of the study plan and other past data. Recommendations are made for the next three year period, 1989-1991. E 7.0 Water Quality The water quality program for the North Anna River was the same as the program for Lake Anna, i.e., temperature and 9-dissolved oxygen were menitored on a seasonal (quarterly) E basis. The water quality stations (NAR-1 and NAR-4) are shown in Figure 27, 7.1 Temperature Temperature data were collected both b.stantaneously and continuously, as prcviously described (see Lake Anna water quality). The data indicate that temperatures ranged

     'from a high of 31.5'C in August to a low of 7.0*C in January.

These temperatures are within previous years' ranges and l I l

                 -                                                                    i demonstrate that the river temperatures more or less mirror ambient air temperature patterns.

The 1988 dissolved oxygen data for the North Anna River continues to indicate that the river is usually 90-100% saturated with dissolved oxygen. Dissolved oxygen concentrations ranged from a high of 10.4 ppm in February to a low of 7.7 ppm in August. These data are also similar to those of urevious years, g i , 5 I i I I I I I 8 / I . I

I 8.0 North Anna River Fishes Studies conducted on the lower North Anna River during 1988 focused on continued monitoring of the fish fo~ age base h and smallmouth bass, Micropterus, dolomieui,. Electrofishing surveys constituted the primary means of data collection for forage fishes, Abundance and distribution data for smallmouth bass and largemouth bass (Micropterus salmoides) were gathered during snorkel surveys. Age and growth data for smallmouth bass were obtained from fish caught by , angling. Forage fish electrofishing surveys were conducted in May, July, and September, 1988. Four (4) stations were I sampled each collection month: NAR-1, NAR-2, NAR-4, and NAR-6 (Figure 28) except for NAR-1 in May (equipment mal-function). An approximately 70m reach was sampled at each station with an electric-seine followed by 10 minutes of B effort with a backpack electrofisher (Virginia Power, 1986). 5 Fish collected by electric-seine and backpack electrofisher were pooled for each station's sample, as in previous years. Snorkel surveys were conducted at five (5) stations from June through Occolar 1988. Stations NAR-1 and NAR-2 were sampled monthly and stations NAR-3, NAR-4, and NAR-5 were sampled twice each month. NAR-1 and NAR-2 were sampled l only once each month in order to maximize study effort at

  • those stutions where both smallmouth bass and largemouth l

bass coexist. l Snorkel survey procedures were employed in 1987 (Virginia Power, 1988). identical to those Three replicate f I m 'y m i T- a v SpotsylvDnia County Lake Antta ?

  • Rt M1 Louesa Co- Rt 658 Louisa County (NAR-1) Hany;[j2 Caroline County Rt 738
  • i Hanover Co I

! Hi 603 A 8 Hanove' Co. (8 n 1 (IJAR 33 Rt 601 % Hanover Co. 8 ' To Fredericksburg (NAR-4) 3 tioet  ; Ha,w,ver Co * (rJAR 5) Rt 1 Hantwer Co

Hanover County (HAR 6) p,,
                                                                                                                                                )
 ,                                                                                                                  c
 -4 0        2       4 M41es                   '                             Rt 667 Hanover Co Kilometers L        b d                                                   e Rt 54                                     L 4p          Hanoves Co.                                 Par _n Sougg                                                                                                         unkey R'm a""a                                                      Ashland To Richrnond Rt 33 Hanover Co.

At 611 Hanover Co. L V Figure 27. Location or the two coneiroous temperature recoraers tx3, ona two monthly instantaneous temperature locations (3), on the North Anna River

Spotsylvania Cout Lake Anna Oqb f Rt.601 1 1 Louisa Co. Rt.658 Louisa County yi (NAR-1) o. i liar ogr h Caroline County j 000 Bt. 738 , Itanover Co I - Rt.603 llanover Co.

                                                                                                                                                                                                                                                                                              \l      I (NAR-3)                                                     A Ot. 601 llanover Co. I (NAR-4)           I To Fredericksburg floel Itanover Co.                         1 (flAR 5)                   L G.

Rt. 1

       /u                                                                                                                                                                                                                                      Hanover County                                                  llanover Co

(" A " *) s

       ?

r'! A 0 2 4 i MJes -

  • Rt 667 llanover Co.

Kilometers 9

                                                                                                                                                                                                                                                                                                                                                                                                ~

i Rt 54 b3Q ! Soun, @8 llanover Co. I f F angd anke>< f Ashland M l ! llanover Co. Rt.611

81. 33 llanover Co. ( -y To Richmont, I

1 I Y l Figure 28. Locations of North Anna River f i sh sarnpl i ng stations. l ens aus se am as as as as me um em sur me aus as sa me aus new

counts of smallmouth bass and largemouth bass were made along two 100m transects at each station, All bass sighted were categorized by species as to young-of-year, stock-size, or quality-size. In addition to size group, all bass b sighted were categorized as to type of cover being used at the moment of sighting, bedrock ledge (Ledge), boulders (Boulder), instream woody debris (Wood), or no apparent cover use (Open). Counts of smallmouth bass and largemouth bass obtained from each snorkel survey were converted to density estimates I (number /100m2 of bankside channel) to account for differ-ences in visibility among survey days and sampling stations. North and south bank transects at each station were treated separately. Monthly mean and maximum density estimates were based on three replicates per month for stations NAR-1 and i NAR-2 and six replicates per month for stations NAR-3, NAR-4, and NAR-5. Detailed habitat availability surveys were conducted at NAR-3, NAR-4, and NAR-5 on 8, 9, and 15 December, 1988. Depth and velocity were measured at 3m increments along 10 transects at each 100m long snorkel survey transect. Within f each 3 x 10m cell of each station's survey gridwork, the percent composition of dominant and subdominant cover types was visually estimated. Cover availability data obtained

       ' from two cells encompassing snorkel survey transects were used     to                   weight cover    utild,:ation   data   obtained   during

{ snorkel surveys. Only observations of cover use obtained l l _ _ *'-__ ..

during the first replicate count of any transect were used. l Following the met. hods of Bovee and Cochnauer (1977), indices of cover preference for smalle'outh bass and largemouth bass in the North Anna River were obtained. Scale samples and associsted length data for smallmouth 1 bass were obtained by angling in 1988. Fish were measured to the nearest mm and released after scale samples were taken. Four scale samples were obtained from smallmouth bass collected from NAR-4 (3 fish) and NAR-6 (1 fish) during 1988 forage fish surveys. Age and growth analyses followed techniques employed since 1985 that are detailed by King (1986). North Anna River Fish Results I A total of 1,771 fish were collected from the North Anna River during forage fish surveys in 1988 (Table 20), y NAR-2 yielded the highest catch followed by, in decreasing U order, NAR-1, NAR-6, and NAR-4 Equipment malfunctions that occurred during May collections prevented sampling of NAR-1 and reduced sampling effectiveness at all stations. For the last three years, the numbers of fish collected at each station have remained in the middle or upper end of the ranges for numbers of fish collected since 1981 with the exception of NAR-4 (Figure 29), although NAR-4 has exhibited the most stable numbers of any station. The 1988 reduced g cerch for NAR-4 is a less drastic decrease than that often seen year to year at other stations, e.g., NAR-6, and _E1 M- . _ -_ _ _ _ _ _ _ _ _ _ _ - -.

M Y O M Y M M W M & W W W Y M M W. M

  M Figure 29. Number of fish collected from the North Anna River during forage finh electrofishing surveys, 1981-1988, by collection year.

d 900 g .l 800 - 700 -

                                                                               \A                      /

l \ / c 600 - NN \ 4

                                                                                                                   \g \

f ,

                                          ,                                 /*(

500 , ,, S I3' E 2 / z" 400 - Ns / - C 300 - 200 2 LQ / ,a 100 N_[ , 7 i , , , ( '81 '82 '83 '84 '85 '86 '87 '88 Year of Collection O NAR-1 + NAR-2 o NAR-4 A NAR-6

                                      =

Table 20, Number of fish collected from the North Anna River I during forage fish electrefishing surveys, 1981-1988, E

                                                                        'by month of collection.                                    5 Year       Station                May    July      Sept      Total 1321          www:1                     3      53       32        13 NAR-2                   56      38      123         217 NAR-4                115        68      308         491 NAR-6               206         76      155        437 Total                425       232       662       1319 1982          NAR-1                    31     52        40        123 NAR-2                138        96        60        294 NAR-4                123        92       334        549 NAR-6                    81    154       102        337 Total                373       394       536      1303 1983          NAR-1                106        43        52        201 NAR-2                   53    158         34        245 NAR-4                190        98       255        543 NAR-6                   68     148       385        601 Total                417      447       726       1590 1984          NAR-1                304        67      134         505 NAR-2                116        60        74        250 NAR-4                101      110       227         938 NAR-6                   37      87        89        213 Total                558      324       524       1406 1985          NAR-1                128      114       126         368 NAR-2                162      154       252         568 NAR-4                118      189       216         523 NAR-6                229      253 g

383 865 5 Total 637 710 977 2324 1986 NAR-1 201 85 73 359 NAR-2 171 139 289 599 NAR-4 179 201 196 576 NAR-6 130 289 279 698 Total 681 714 837 2232 l g 1987 NAR-1 411 106 208 725 NAR-2 182 153 401 736 NAR-4 145 119 128 392 NAR-6 98 166 143 407 Total 836 544 880 2260 1988* NAR-1 290 102 72 464 NAR-2 220 243 105 568 g NAR-4 109 88 137 334 5 NAR-6 M 108 297 405 - Total 619 541 611 1771 E

I E may be partially attributable to reduced sampling efficiency l in May. The five most abundant species collected during 1988 were, in decreasing order, Notropis procne, L analostanus, l Lecomis auritus, N. rubellus, and Percina Deltata (Table 21). These five species accounted for 76 percent of the catch from the North Anna River in 1988, and have accounted for 67 and 59 percent of the pooled May, July, and September catches in 1987 and 1986, respectively. Species richness was reduced at NAR-1 and NAR-2 in 1988 (Figure 30), following a general increase in the number of species collected at all stations since 1981 that paralleled increases in the numbers of fish collected (Figures 29 and 30). Snorkel surveys for 1988 were conducted between 0930 and 1500 hours at river temperatures ranging from 11.0 to 29.9'c and underwater visibilities ranging from 1.0 to 4.0m. Distributions of smallmouth bass and largemouth bass were similar to those observed in 1987 and previous years (Table 22). Scullmouth bass were more numerous at the j downstream stations, NAR-4 and NAR-5, and largemouth bass were more numerous at the upstream stations, NAR-1 and NAR-2 However, a major difference between results obtained in 1988 and 1987 was documentation of smallmouth bass

             ' inhabiting the upper reaches of the North Anna River at j             NAR-2 in 1988.        Although there have been annual increases in the   abundance       of  smallmouth      bass   at   NAR-3    since   1985 I
     - . . .                                      DC,

Figure 30. Number of fish species collected from the North Anna River during forage fish electrofishing surveys, 1981-1988, by collection year. e

                                         ^

24 23 - 22 -

                                                                                           \       s>

21 -

       , 20 -

o [ 19 x s & In I o 18 - e 1 D 17 - " E 3 z 16 -f - 15 - \ 14 -

                    \\

13 - 4

          '2                 .
                                                    '84            '85         '86     '87        '88
              '81           '82         '83                                                                '

Year of Collection

                                     +-     NAR-2             O      T4AR-4         A NAR-6 O     NAR-1 M   M    M M W      W    W       WW W        W       M      W     M    M  M W W W M

p' y sumuu imamur u u 'u i table 21. Number of fish collected from the North Anna River during forage fish electroffshing surveys, 1981-1986, by year of collection. n Species 1981 1982 1983 1984 1985 1986 1987 1988 l Acantharchus pomotis 0 0 0 0 1 0 0 0 Anguilla rostrata 78 69 78 73 109 71 120 60 Aphredaderus sayanus 1 0 0 0 0 0 0 1 Catostomus commersoni 2 0 0 0 14 0 0 0 Centrarchus macropterus 0 1 0 0 0 0 0 h Dorosoma cepedianum 1 0 0 0 0 1 0 0 Erleyron oblongus 1 0 4 0 1 6 2 1 Esom americanus 0 0 0 0 0 0 0 2 Esom niger 7 0 3 3 2 3 3 0 Etheostoma olmstedi 21 4 13 10 26 20 15 3 Etheostoma sp. 0 0 0 0 0 e 1 0 17 15 3 46 46 23 22 Etheostoma vitreum 18 Hybognathus regius 0 1 36 0 8 45 11 7 5 6 112 64 $? 14 Hypentellum nigricans 2 1 8 7 0 1 2 3 7 12 tctaturus natells 0 3 4 1 0 3 letalurus nebulosus 0 '. 0 letalurus punctatus 0 0 1 0 0 0 1 tampetra appendia 0 0 0 1 1 0 1 2 249 221 240 187 356 260 tepomis auritus 220 149 2 O tepomis gibbosus 2 4 12 12 1 1 e tepomis gulosus 0 0 0 0 0 0 1 1 9 30 24 6 7 35 15 teposts macrochirus 25 tepomis microlophus 0 0 0 1 0 0 11 15 Hicroptesus dolomleul 1 0 2 6 2 7 2 4 Nicropterus salmoldes 5 1 7 5 3 12 3 5 0 2 5 0 0 0 0 Norone americana 1 Homostoma macrolepidotum 0 0 0 0 5 5 0 1 Nocools leptocephalus 64 47 25 13 88 58 36 14 Nocoals micropogon 57 34 46 56 93 134 62 36 0 1 0 0 0 0 0 0 Nocoals sp. 8 73 1 3 35 24 Notemigonus crysoleucas 1 2 5 3 52 61 20 64 85 to Notrepis amoenus 152 329 Notropis analostanus 340 273 286 1% 325 381 0 0 34 23 126 134 105 6? Notropfs erdens 0 0 0 0 Notropis cornutus 0 1 0 0 0 0 0 0 0 0 0 1 Notropis budsonius 401 670 477 Notropis procne 236 472 4E0 338 432 26 63 41 62 102 208 251 174 Notropis rubellus 0 0 0 0 Notropis sp. 0 0 0 1 0 0 0 0 1 0 0 0 Noturus gyri ws 51 36 34 38 138 165 155 s04 Noturus insI pls 0 1 0 0 2 0 Perca flavescens 1 1 0 0 Percina notogramma 0 1 0 1 2 1 j 41 136 157 140 83 110 Percina peltsta 50 31 Petromyron marinus 0 0 3 10 0 12 1 1 0 0 0 1 0 0 0 0 Phominus creas 0 0 Pomonis nIgromaeutatus 13 4 42 13 0 0 Semottlus corporalls 50 18 40 5 186  % 46 12 r e

Table 22. Number of smallmouth bass and largemouth bass observed during 1987 and 1988 snorket surveys. a Smallmouth bass targegouth bass 1987 1988 1987 1988 Replicate Station Bank Count n SP0YOY SMB 11 SMB 11 n $MBYOY SMB 11 SMS 11 n 1HBYoY IMB 12 tre 12 n tMOYOY 1MB 12 (M8 12 NAR-1 North 1 4 0 0 0 5 0 0 0 4 0 0 's 5 to 3 2 2 4 0 0 0 5 0 0 0 4 0 0 1 5 9 2 2 3 4 0 0 0 5 0 0 0 4 4 1 2 5 11 3 2 South 1 4 0 0 0 5 0 0 0 4 2 0 2 3 2 5 3 1 3 4 0 0 5 0 0 0 4 0 0 1 1 5 2 1 1 3 4 0 0 5 0 0 0 4 1 0 5 7 1 0 0 MAR-2 North 1 4 0 0 0 5 0 4 0 1 1 1 0 5 3 2 1 2 4 0 0 0 5 0 0 0 4 2 0 0 5 9 7 1 3 4 0 0 0 5 0 0 2 4 0 1 3 5 6 2 0 South 1 8 0 0 0 5 1 2 3 4 0

;$                                                                                                                    5      1           5         6         6    3 2
  • O O O 5 0 0 2 4 0 0

2 1 5 3 5 3 3 a 0 0 5 1 2 2 4 5 2 1 5 5 2 1 HAR-3 North 1 8 1 4 0 10 3 0 8 1 1 1 0 to 1 2 1 2 8 1 1 0 to 2 0 1 8 0 3 0 to 1 1 1 3 8 1 10 0 10 4 0 0 8 1 3 0 to 2 2 1 South 1 8 0 0 2 10 3 2 0 8 0 7 5 to 4 3 2 2 8 0 7 2 10 1 8 4 8 0 4 4 3 8 0 to 5 7 0 1 2 to 4 3 3 8 0 2 3 10 5 3 0 RAR-4 North 1 to 5 8 1 10 9 2 3 to 0 5 1 to 0 0 0 2 10 9 12 3 10 14 2 2 to 0 6 2 10 0 0 5 3 to 5 14 2 to 20 3 1 ?O O 8 2 South 1 10 2 8 to 1 0 0 3 to 11 8 2 to 0 0 0 2 to 7 16 to 0 0 0 3 10 10 6 0 to 0 0 0 10 to 0 0 0 3 7 to 0 10 15 11 1 to 0 0 0 to 0 0 0 NAR-5 North 1 10 3 30 12 10 18 22 7 to 0 2 2 to 1 3 2 2 10 4 26 6 10 24 19 10 In 0 3 3 to 0 1 4 3 to 5 30 9 to 20 21 7 to o 2 4 to 0 4 2 South 1 10 2 4 0 to 11 3 1 10 0 0 5 10 0 0 1 2 10 4 10 0 to 8 2 3 10 0 0 10 1 10 0 2 0 3 3 9 1 to 8 4 0 to 0 0 0 10 0 1 0 g g M M M E E N O O N N

i I - l (Virginia Power, 1988), prior to 1988 records of sna11 mouth bass occurring upstream of NAR-3 were rare and limited to .l single specimens. Repeated observation of smallmouth bass at NAR-2 during 1988 and observation of young-of-year are indicative of continued upstream expansion of this species' range. Density estimates for smallmouth bass and largemouth bass derived from 1988 count data and visibility estimates were also similar to those obtained in 1987 (Table 23). NAR-5 north bank consistently exhibited the greatest mean and maximum smallmouth bass densities, as in 1987 Large-mouth bass densities were greatest at NAR-1 north bank in 1988. NAR-2 south bank also exhibited high densities of largemouth bass, as in 1987. In both years, variability in mean density estimates was heavily influenced by zero fish counts for many replicates. Variability between the north and south banks of any station was related to habitat complexity: fewer fish were observed along banks character-ized by monotypic habitat than along banks with a variety of habitat types. Seasonal trends in smallmouth bass and largemouth bass abundance at NAR-3, NAR-4, and NAR-5 were examined oy pooling monthly mean density estimates for each station's north and south bank (Figures 31-33). Two strong seasonal

     ' trends were apparent. A consistent trend of smallmouth bass densities decreasing as the sampling year progressed was exhibited                     at   NAR-4   in both     1987   and   1988  (Figure 32).

_no_

Figure 31. Mean bankside channel densities (No./100 m2) of smallmouth bass and largemouth bass greater than 120 mm total length estimated for NAR-3, 1987 and 1988.

                  .                                                          NAR-3 Both Banks Combined 0.5        - - - - - -           -      -       - - - - - - - - - - - - - - . - -                        -     - - - - - - . - - - - - - - - - - . - - .-

1 1 0.4 - n N E o o c / ( O.3 - yk

  • d / \.

8' z N. x

                                      \                  /                                        f            's                                              N
                                                                                                                                                                   \s
                                        'N V                                           /           \

c O.2 - s-A_ N Ns O ' N u / s,a

                                                     \              ,

l 2 'v'N ' s.  %

                                                                                                                                                                                  .L O.1 -                                              N
                        /                                                             \

11 0- I i i i.> Jun Jul Aug Sep Oct Month O SMB '87 + SMB'88 o LMB '87 A LMB '88 M M W W M M M M M M l3 3 g M W M M M M w, y i -

W W W W M M M M W W W M M M W W W W W Figure 32. Mean bankside channel densities (No./100 sa2) of smallmouth bass and  ; largemouth bass greater than 120 mm total length estimated for NAR-4, 1987 and 1988. NAR-4 Both Banks Combined 4 1 1 0.9 - , 1 1' 0.8 - s n

   }o   0.7 -

O ( O.6 - e d < s 5 q x O.5 - B' ya g _

                                                                     /

N O.3 - \ - x 0.2 - 0.1 , s,

                                                                                                \x N      -

u O

                                           +

F i 7' r -- Jun Jul Aug Sep Oct Month D SMB '87 + SMB '88 o LMB '87 A LMB '88

Figure 33. Mean bankside channel densities (No./100 m2) of smalImouth bass and largemouth bass greater than 120 mm total length estimated for NAR-5, 1987 and 1988. NAR-5 Both Banks Combined - 1- --

                                                                                                                                                                                           --------n----                                          - - --                       - -                                --         -         -

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                                                                                                                                                                ,,.                        . . - . - - + -                                               - s. - .                                                                     <

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                                                                                                                                                                                                                                                                             'w. '

i i ' M. Jun Jul Aug Sep Oct Month n SMB'87 + SMB '88 o LMB '87 A LMB '88

                                                                                                                                                             =s .. == == == == == == == =

a= == =

                            -              _       m                                                                               _
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                                         -    l ue-25          20          58             86             _            _ ym            66 75 00 0 65 0,

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M- 0n _ - 84 t y 33 79 92 - 73 26 u 14 03 12 92 y 17 8 77 o . - _ l e- . . . . . . . . 33 23 11 0 20 ms - hng- 00 00 00 00

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_ xd- . . . . . . . . N -  ! M- - ae00 00 00 0 00 S- _ - - MM- - ( l e - - a_ - sk - - ym 06 08 99 00 37 66 L_ - 00 15 65 0 03 er _ l ue- . . . .

                                                                                                                              -        -         ym           56       35 35                     0

_ l ue- 58 hmg_ - io - 10 11 . . . 10 . t n i s s 7 8 _-oar- tin nxa _ - - - 00 88 00 hmg00 tin - - 00 00 1 00 _ n8 e8 - 9_MM 1-00 00 11 00 40 _ 8- _ 9 nxa_00 oar 00 05 02 00 00 0 0 00 00 d9 - 00 _ 1 _- MM 00 1 00 00 0 00 a n_ _ _ ud on

                                  -             na_                                  96          96             88
                                                                                                                              -       -                n-i a ai                -        --        00          12             51
                                                                                                                                      -            na         11       44         54             3             60 ed                                                                                                 ai        11        02 x

a7 MM-e _- 00 00 00 ed-Me 00 01 0-00 m8 _ 00 00 0 00 9 _ - _ M-74 - d1 y 26 34 - - _ 20 n 11 44 92 56 99 6 64 am _- _ l e- . . . . . .

                                                                                                                             -                  y            22       13          02            5

_ hng - _l e- 21 o - 00 00 00 . . nr _ tan-nea hng00 tan- - - 00 00 0 00 af e oMR-00 00 66 00 30 _ nea 00 08 00 0 10 00 md M . . . . . _ oHR_00 00 00 0 00 e 00 00 00

                                                                                                                            -                  M               . .       . .              .       .             . .
                                                                                                                            -                               00        00 yt                                                                                                                                                                            00            0              00 l a h m
  • hh hh hh hh t i nt k__hh n ru tt tt ru ru tt tt ru tt ru k hh hh tt tt hhtthh tt hh tt os a oo oo oo oo oo n ru ru ru ru ru Me B NS NS NS NS a oo oo oo oo ll S B NS NS NS NS NS oo
                                                                                                                                                                                                            ~

n 3 o 1 2 3 4 5 n-2 i - - o1 2 3

                                                                                     -           -              -                                                                              4              5 e                                               t= R                 R           R           R            R                                        i- -             -          -             -             -

_ l a= A A A A A tR R R R R b t- N N N N  ! aA A A A A a S- -  ! t - N N N T S_N N 3 1f

I E Conversely, at NAR-5 smallmouth bass densities appeared to increase through the sampling years (Figure 33). It is unknown whether these trends reflect actual changes in fish abundance or behavioral changes in the fish. No definite l seasonal trends could be identified for smallmouth bass at NAR-3 or for largemouth bass at any station. It is probable that densities of smallmouth bass and largemouth bass in - these areas were too low to allow for trend detection. Smallmouth bass and largemouth bass observed at NAR-3, NAR-4, and NAR-5 during 1987 and 1988 snorkel surveys l exhibited distinct cover utilization preferences (Figure 34). Smallmouth bass exhibited a strong preference for overhanging bedrock ledges, whereas largemouth bass exhibited a strong preference for instream woody debris. When ledge and woody cover comprise a relatively low percentage of the total amount of habitat available at most stations (Table 24), they serve as fish concentrators. 3 3 Further, cover availability may affect smallmouth bass and largemouth bass distributions, e.g., the two transects that possessed the least amount of woody debris, NAR-4 south bank and NAR-5 south bank, were also the transects from which the lowest densities of largemouth bass were observed. In the case of NAR-4 south bank, no largemouth bass were observed over two years at a transect where availability of woody

  • debris was very low (1.0%).

A total of 36 smallmouth bass scale samples were examined for 1988 age and growth analyses. Fish collected

                                                                       .R.-

M E E E E E E E f g g g W M M M M M Figure 34. Cover ut iliza tion preferences of smallmouth bass and largemouth bass i derived from cover availability and cover use data obtained from NAR-3, NAR-4, and NAR-5 in 1987 and 1988. Replicate 1 Data l#R-3. 4, & 5 l l 0.9 , 0.8 0.7 0 c 2 0.6 b b 1 0.5 m y 0.4 - 0.3 0.2 , 0.1

                                                                                                                 +

0 . , . _ . . . . . , . . , .. . .. ._, , .. Ledge souider wood op.n E Smallmouth bass Largemouth bass

             ..                                     g

Toblo24. Habitet availability data for NAR-3 NAR-4, and NAR-5 obtcined during 1988. Standard deviations for mean

               ,    width, depth, and velocity values are in parentheses.

Mean Mean Mean Width Depth Velocity Station N (m) N (m) N (m/s) NAR-3 10 26.93 82 110.4 82 0.069 (2.17) (38.95) (0.041) NAR-4 10 34.66 109 84.08 109 0.066 (1.61) (39.19) (0.062) NAR-5 10 34.62 108 81.37 108 0.064 (2.04) (32.86) (0.040) I Site Cover Availability (%) Station Bank Ledge Boulder Wood Open _. __ . B NAR-3 -- 1.5. 1.5 7.8 g 89.2 NAR-4 -- 17.6 17.4 5.4 59.7 NAR-5 -- 4.1 13.9 6.2 75.7 E E Station Bank

                       ?5*"""EI_S2!*5_^!"!_l*I! 13? 2). _

I Ledge Boulder Wood Open HAR-3 North 3.0 2.0 9.5 85.5 South 0.0 1.0 26.5 72.5 NAR-4 North 12.5 26.5 16.0 45.0 South 11.0 14.0 1.0 74.0 , NAR-5 North 13.0 24.5 10.0 52.5 South 2.0 9.0 1.5 87.5 I

                                                                                                    .a.
                                               -Q6.

I l in 1988 ranged from 91 to 489mm total length and ages 0-7. l Addition of backcalculated length data for these fish to the North Anna River data base (Table 25) had little effect on previously reported mean lengths at age (Virginia Power, 1988). Growth of smallmouth bass in the North Anna River continues to exceed Virginia (Smith and Kauffman, 1982) and national (Carlander, 1977) averages for riverine environ-ments. I Recommendations for the study period 1989-1991:

1. Continue monitoring of North Anna River forage fishes under the present sampling design.

I

2. Continue monitoring smallmouth bass and largemouth bass via snorkel surveys. The intensity of effort will be reduced to sampling twice per month during July, August, and September. Monitoring of four study sites should provide sufficient information to detect any changes in population trends.
3. Smallmouth and largemouth bass collected during routine downstream surveys will be utilized in an ongoing age and growth study to be supplemented by the collection of up to 50 scale samples from both smallmouth bass and largemouth bass every third year. The data will be pooled and reported on a three-year basis. This should allow changes in growth patterns , if any occur , to be detected.

I .07

Table 25. Mean back-calculated total lengths (mm) for smallmouth bass collected from the~ North Anna River, 1983-1988, by year-class and for all years combined. Samples sizes by age and year-class are in parentheses. Age , Year Class 1 2 3 4 5 6 7 1979 101 (6) 181 (6) 249 (6) 297 (4) 378 (3) 389 (1) 1980 103 (11) 201 (11) 272 (11) 336 (6) 401 (2) l 1981 111 (22) 204 (22) 272 (22) 340 (6) 409 (3) 469 (1) 477 (1) l 1982 127 (9) 228 (9) 304 (3) 389 (2) 415 (2) 434 (2) ' f$ 1983 121 (26) 199 (13) 290 (4) 370 (2) 390 (2) 1984 113 (31) 231 (21) 2nB (7) 290 (3) 1985 137 (20) 221 (12) 272 (6) 1986 117 (20) 214 (13) 1987 99 (8) Age 1 2 3 4 5 6 7 Mean 117 212 272 332 398 432 477 s.d. 24 33 34 47 41 28 0 Min 58 129 2( 3  %,1 323 389 477 Max 199 286 362 399 457 469 477 N 153 107 59 23 12 4 1 l M M M M W E E E E E E E gg g M M M

I l
  • I -

9.0 Study, Plan Recommendations for 1989-1991 Throughout this report, which summarized the results of the three-year study period 1986-1988, recocnendations have been made I at the end of each section for the next three-year study period, 1989-1991. The following is a list of those recommendations with appropriate justifications. l l- Recommendation Justification

1. Discontinue the water This program is largely a i quality, temperature and duplication of effort.

dissolved oxygen monitor- Surface temperatures are ing program, I monitored by the ENDECO continuous recordtrs and dissolved oxygen is j monitored during biologi-

  ;                                                                    cal programs,
2. Continue the thermal Quarterly plume surveys and t plume and surface ENDECO ENDECO monitoring are required survey programs, by the NPDES Permit.

I 3. Continue quarterly gill Adult fish studies in Lake net collections of adult Anna have continuously I fish in the lake and WHTF at the six historical stations, indicated the presence of a healthy, diverse fish population. However, I 4 Continue quarterly elec-trofish collections in continued monitoring of fish population, the highest trophic level in the lake, the I the lake and WHTF at the would detect changes that may JB nine historical stations, occur to the ecosystem. Also, 3 fish are a valuable resource d

5. Continue cove rotenone and should be monitored for I studies in conjunction with representatives of the Virginia Department possible changsu caused by' increasing fishing pressure and residential development on of Game and Inland the lake.

Fisheries as per their 8 schedule.

6. Continue to monitor and These structures need to be
  • maintain the artificial monitored and refurbished fish structures in the periodically to maintain their l

I lake. usefulness to the fish popula-tion,and anglers in the lake. I l B ____-94-_ _ _ _ _ _ _ _ _

I I I

7. Continue the largemouth bass age and growth Extensive data collection and prog w t,; 'scing fish analysis of these two species collected during routine in Lake Anna have indicated sampling. Re consistent growth rates three years, port every comparable to other Virginia lakes. This substantial data
8. Continue the striped bass base has characterized both age and growth program by species very well. The- da ta using fish collected would be pooled over a three during routine sampling. to four-vear period, to coin-Report every three years, cide with rotenone surveys, for subsequent reports.
9. Continue the summer habirat survey program in the lake, continue to monitor the summer anoxic hypoli=nion in the lake by quarterly pluuc survey to l

determine any changes in the habitat availaole to striped bass.

10. Discontinue the macroben- Historical data indicate the thic Corbicula sampling adult Corbicula population has program, remained relativety stable.

The presence of Corbicula in the system has not impeded the operation of the pouer station nor had a negative impact on the lake ecosystem.

11. Discontinue the Chloro- E phyll (a) sampling A large data base currently E program, exists that cufficiently coaracterizes Lake Anna.

Generdl trends have remained consistent over time and no deletecious effects have been identified.

12. Continue monitoring the These sampling programs are North Anna River forage necessary ta detect any 3 fish three times per year, changes in population trends B spring, summer and fall, of the river fish assenblages, at the four historical The river fishes are an impor-stations.

tant resource susceptible, to l'3. Continue monitoring the some extent, to changes in the North Anna River game fish lake which is its primary species (smallmouth and source of water, nutrients, largemouth bass) via etc. The reduced snorkle snorkle surveys. Reduce sampling program should be the intensity of the study sufficient to determine population to six surveys per year at changes wran each of four sites. compared to present baseline data. l

                              .1AA
                ~

I

14. Continue to study age and This reduction of scale sampl-I growth of river smallmouth and largemouth bass by using data from routine ing effort will reduce pressure on the river game fish species while still m surveys. Additional scale allowing the cetection of any 3 samales, up to 50 from changes in growth patterns.

bot'a species, will be collected every third I year. The scale data will be pooled and reported every three years. I

   -15. A yearly summary report of    A yearly summary report should results will be submitted     be sufficient to monitor to include figures and        progress on the Lake Anna tables of data with           study plan.

discussion of trends and I changes. I I I I I I I I . I I I s -

l

                                            ~

Literature cited Bovee, K. and T. Cochnauer. 1977 Development and evaluation of weighted criteria probability-of-use curves for instream flow assessments: Psper 3. Fisheries. Instrean Flow Information FWS/0BS-77/63. U.S. Fish and Wildlife Service, Fort Collins, Colorado. Carlander, K. D. 1977. volume 2. Iowa-State Handbook Universityof freshwater Press. Ames, fishery biology, Iowa. l Everhart, H. W. and W. D. Youngs. 1981. Principles of fisherv science. Cornell University Press. Ithaca, New York. ' 3 3 Heidinfsh.er, R. C.State and K. Clodfelter. 1987. Age and Growth of F lowa University Press. Ames, Iowa. Hile, R. 1941. rupestris Age and growth of the rock bass Ambloplitea (Rafinesque) in Nebish Lake, Transactions 33:189-337. of the Wisconsin Academy of ScienceWisconsin. and Arts. King, M. A. 1986. A comparative tion of Micropterus dolomieuistudy ( str of growth and distribu.

                                                                                 ',.1mou th bass) from the lower dmont sections Rivers , pieVirginia.            of the  'Wrth Haster of Science     Anna and South Anna thesis,   Virginia Commonwealth University, Richmond, Virginia.

O'Gorman, R., growth of D. H. Barwick and C. A. Bowen. 1987 fish. Iowa-State University Press. Ames, Iowa. Age and Pikitch, E. K. snd R. L. Demory. 1988. Assessment of scales as a means of agin Dover sole. Fishery St.fiety 17:4 Transactions of the American E Sharp, D. and D. R. Bernard. 1988. Precision of estimated ages 5 of lake trout from five calc Q 4 American Journal of Fisheries Managemen. 8:3. structures. Morth Smith. P. and J. Kauffman. 1982. Age and grceth of Virginia's g freshwater fishes. Virginia Coccission if Game and Inland Fisheries Technical Report. Virginia Comaission of Game and Inland Fisheries, Richmond, Virginia. Virginia Power. 1983. Environmental study of Lake Anna and the lower North Anna River. Annual report for calendar year 1982. Volume II. Virginia Power, Richmond, Virginia. Virginia Power. 1986. Anna Power Station. Section 316(a) demonstration for North Virginia Power, Richmond, Virginia. Virginia Power. 1987. Environmental study of Lake Anna and the

                            . lower North Anna River:              summary report 1986.           Richmond, Virginia.

Virginia Power. 1988. Environmental study of Lake Anna and the lower North Anna River. Annual report for calendar year 1987. Virginia Power, Richmond, Virginia. g Zar, J. H. 1984 Biostatistical analysis. E Prentice-Hall, Inc. Inglewood Cliffs, New Jersey. g

                                                                  -107-

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COMMONWEALTH of VIRGINIA STATE W'ATER CONTROL BOARD n~ os. e~ 2111 Hamilton Street soma ununnas n  % I ^*es. t OH<e Boa 19143

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Manager Water Quality M. Marshal g

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w s, m n.or anwi c wea a9= Virginia Power 500 Dominion Boulevard Glen Allen, Virginia 23060 Dear Mr. Marshall Tnis is in response to your letter of May 15 regarding results of the 1996-8B environmental -,,tudy of Lake Anna and the lower North Anna I river and ?gequested modifications to the sampling program. Regional and headquarters staff have reviewed the study plan I recommendations for 1989-1991 and concur that all programs other than the chlorophyll and Corbicula sampling and monthly water quality surveys be continued. Lake Anna is included in our agency statewide I ambient lake monitoring program so we will continue to obtain chlorophyll a and water quality data through our surveys of this lake. In your letter you indicated that the modifications would be initiated on June 1, but Jean Gregory of my staff notified Carter Cooke on that date that agency review comments would not be available I until the week of June 5. topic that Jean Gregory rather than R. W. Ayers should be the headquarters technical contact. Please note for future mailings on this Thank you for the opportunity to comment. Sincerely, (f I . Richard N. Burton Executive Director

c. Mr. R. W. Ayers I Mrs. J. W. Gregory Mr. W. L. Kr.gloo Mr. C. Cooke I

I

                          . . ~ . - .

I May lE, 1989 Mr. Richard N. Burton Executive Director Virginia Water Control Board 2111 N. Hamilton Street g Richmond, Virginia 23230 3

Dear Mr. Burton:

Enciosed for your review is the 1988 Annual Report of the environmental study of Lake Anna and the lower North Anna River including a summary of results from 1986-1988. This report represents completion of the first three year E study period following the successful 316(a) study. 5 Analyses of data collectec during this three year period suggest no major changes have occurred in the lake or the river ecosystems. Lake Anna and the North Anna River support healthy, well-balanced ecological communities which have changed little since the 316(a) study. In v1ew of the 1986-88 results and the post 316(a) agreement which called for a review of the study program b B at the end-of each three year V.udy period, Virginia Power hereby reouests selected reductions in sampling effort for the next three year period n (1989-1991). These changes are specified in the accompanying report. g There is no change anticipated in station nperation in the future and the programs which will be continued include: the thennal plume surveys and surface ENDECO temperature recorders; adult fish studies, including age and growth of game fish, in the lake and river; ano the artificial fish structure program. The programs which we propose to eliminate include: chlorophyll (a) a sampling; Corbicula sampling; and monthly water quality surveys, g Further, after three years of funding graduate research assistantships for work on Lake Anna, this program will be discontinued due to limited response to the program and the lack of apparent justifiable topics. We plan to initiate these modifications to the sampling program on June 1, 1989. If you or your staff have any questions or coments relative to the E g modifications, please contact either Mr. Bill Bolin (257-4777) or Mr. Carter Cooke (257-4952). Sincerely, P.E. Manager Wat'er Quality Enclosure cc: Mr. R. W. Ayers (enclosure) Mr. W. L. Kregloe l W Mr. T. Gunter (enclosure) Mr. K. N. Kappatos I

I I E1HIBIT 4 Changes in Special Conditions

1. Special Condition 4 must be eliminated.
2. Special Condition 6 should be amended as follows:

Except as provided below in this Special Condition, the findings of fact and conditions set forth in the 401 certificates issued by the Board on I August 29, 1973, and the 21(b) certificate as amended on February 11, 1972, are incorporated herein by reference as limitations and shall continue in full force and effect. These certificates may be revised in l the future. Upon the completion of any amendments, the revised I certificates shall be incorporated herein by reference as specified above. Any findings of fact and conditions in the 401 and 21(b) l i i certificates relating to thermal discharges, temperature water quality I standards, and temperature monitoring are superseded and of no further effect, but those discharges, standards, and monitoring requirements are subject to the effluent limitations and special conditions set forth in this permit.

3. Special Condition 9 should be amended as follows:

The temperature monitoring program shall be done in accordance with the following schedule and identified in accordance with accompanying Charts

                 #1 and #2.      Reporti are to be submitted quarterl within 90 days of the end of the quarter in which the readings were co lected.
1. Fixed Continuous Temperature Recorders as noted on Chart #1.  !

a) Temperature measurements are to be taken hourly at the surface at Stations 1 through 9 inclusive and 11 and at a depth of 3 meters at Station 10. l b) Temperature readings shall be reported as follows:  !

1. Monthly maximum daily temperature in degrees Celsius.
2. Mean of daily high, mean and low values in degrees Celsius.
2. Quarterly, Thermal Plume Survey Network as noted on Chart #2.
a. Temperature measurements are to be taken during daylight hours from the surface to the bottom at one meter intervals at Stations A through N on Chart f2.

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I I ATTACHMENT 2 I I I I I I

l COR 14 - NPDES Permit Reissuance 1990 I May 10, 1990 Mr. William I.. Kregloe Virginia Water Control Board Valley Regional Office 116 North Main Street P. O. Box 268 Bridgewater, VA 22812 RE: REQUEST FOR CHANGE TO DRAFT VPDES PERMIT - NORTil ANNA POWER STATION

Dear Mr. Kregloe:

The recent draft permit for North Anna included monitoring reouirements and effluent limitations for chlorine at four small package sewage treatment plants. We questioned the reasonableness of daily monitoring at these low flow, intemittent discharges and asked that the monitoring frequency be reconsidered. We realize that reissuance of the pennit has been delayed in part because of this request but the original draf t requirements were based on a municipal sewage tr)atment works scenario which discharges at more or less constant flow at all times. This scenerio is not at all similar to our treatment plant activities. Hopefully, we can now agree that Water Board policy allows for more workable permit conditions. North Anna's treatment plants, which discharge to Outfalls 005, 006, 007 and 008, have average flows less than 1000 gallons in a 24 hour period. Plants discharging to 006 and 008 have flows less than 1 gallon / min at all times. -E Plants discharging to 005 and 007 may intermittently be as much as 3 gal / min E but on average would be less than 1000 gallons daily. The more appropriate moni toring frequency for chlorine at these small plants is once/ month and we E request changes to the draft permit that incorporate this frequency. g it seems appropriate to include a recent development as a special condition in the VPDES permit since issuance has already been delayed. This situation was brought to our attention recently by the Virginia Health Department We request that a special condition be added to the pemit to authorire land application of backwash from three particle separators and one sand filter. Backwash from the particle separators and sand filter will be discharged in the immediate vicinity of several drinking water wells at the station. The attached map indicates the locations of the three wells involved. Mica, sand and grit have appeared in water produced by a new well installed at the Information Center (NANIC). The amount of this material required that a particle separator and a sand filter be inserted in the flow path. This type of particle separator is housed in a cylindrical tank. Water enters the top of the separttor, then goes through a series of chambers and baffles, slowing its velocity. This allows particles to settle to the bottom of the tank and they are washed out once per day. The amount of this backwash is no more than 10 gallons. E

Mr. William L. Kregloe May 10, 1990 Page 2 A sand filter is needed for further clarification of the water. The sand filter requires backflushing and " fluffing". Backflushing with all attendant I rinses would produce an additional 75 gallons of effluent also requiring isnd application. I Sand and grit have also been produced by other of the station's working wells, Nos. 4 and 6, though to a lesser extent Smaller sized particle separators without sand filters added are recormlended for these wells. The backflush for these would be approximately 5 gallons / day. There is sufficient land area around each of the wells to accomodate land application, at least 400 sq. ft. each, and it has been demonstrated that the areas percolate. Attached you will find a copy of results from tests conducted by Hutcherson Soil Consultants so indicating. I We appreciate your consideration of these changes and additions. mutual best interest to construct the most workable permit possible and to authorize the backwashes in this efficient manner. It is in our If you have questions regarding the information submitted or our requests, please contact G. R. I Knauer of my staff at (804) 273-2996. Sincerely, tuo

 ,   B. M. Marshall, P.E.

Manager Water Quality I bc: J. L. Wilson G. E. Kane K. N. Kappatos W. A. Thornton I A. H. Stafford A.C.Cooke9phij

0. P. Sloan p I K. L. Williamsen Kh(yp J. J. Olka p0 bows i @

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