Text

Environmental Study of Lake Anna & Lower North Anna River; Annual Report for 2000 Including Summary for 1998-2000
	ML021680344
Person / Time
Site:	North Anna, 05200008
Issue date:	05/21/2002
From:	Chutima Taylor; Dominion Resources
To:	Faha T; Office of New Reactors, State of VA, Dept of Environmental Quality
	Kugler A, NRR/DRIP/RLEP, 415-2828
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SDominion May 21, 2002 Thomas A. Faha DEQ - Northern Regional Office 13901 Crown Court Woodbridge, VA 22193

Dear Mr. Faha:

In accordance with the post 316(a) monitoring agreement, enclosed for your review is the latest Annual Report for Lake Anna and the Lower North Anna River including a review for the period 1998-2000. The data indicate that Lake Anna and the Lower North Anna River continue to support a well-balanced ecological community and both remain some of the finest recreational resources in Virginia.

Please let me know if you have any questions concerning this information as well as any other ongoing environmental monitoring for North Anna Power Station.

Sincerely, C. C. Taylor Director - Electric Environmental Services cc:

w/enclosure Mr. John Odenkirk Virginia Department of Game and Inland Fisheries 1320 Belman Road Fredericksburg, VA 22401 cjb527/word/sjh

ENVIRONMENTAL STUDY OF LAKE ANNA AND THE LOWER NORTH ANNA RIVER ANNUAL REPORT FOR 2000 INCLUDING

SUMMARY

FOR 1998-2000 4

Prepared by:

ENVIRONMENTAL BIOLOGY ELECTRIC ENVIRONMENTAL SERVICES "I

ENVIRONMENTAL STUDY OF LAKE ANNA AND THE LOWER NORTH ANNA RIVER ANNUAL REPORT FOR 2000 INCLUDING

SUMMARY

FOR 1998-2000 Prepared by:

ENVIRONMENTAL BIOLOGY ELECTRIC ENVIRONMENTAL SERVICES In an effort to conserve our natural resources, this report is being printed on both sides of recycled paper.

TABLE OF CONTENTS PAGE Executive Summ ary.......................................................................................................

1 List of Figures................................................................................................................

1..iii List of Tables....................................................................................................................

V 1.0 Introduction.......................................................................................................................

1 2.0 Station Operation..............................................................................................................

2 3.0 Lake Anna..............................................................................................................

3.1 Temperature....................................................................................................

2 3.2 Fish Population Studies - Gill N etting Results................................................

4 3.3 Fish Population Studies - Electrofishing Results..............................................

6 3.4 Aquatic Vegetation.........................................................................................

10 3.5 Conclusions.....................................................................................................

12 3.6 Recom m endations..............................................................................................

13 4.0 North 4.1 4.2 4.3 4.4 4.5 Anna River............................................................................................................

13 Tem perature.......................................................................................................

13 River Flow......................................................................................................

14 Fish Population Studies - Electrofishing........................................................

15 Fish Population Studies - Direct Observations..............................................

19 Conclusions.....................................................................................................

23 5.0 Literature Cited...............................................................................................................

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Executive Summary Following the successful completion of the North Anna Power Station 316(a) Demonstration in 1986, Dominion (the Company) agreed to continue selected environmental monitoring studies on Lake Anna and the North Anna River. Correspondent with the recommendations in the three-year review ofpost-316(a) studies for 1989-1991, the Company requested and was granted a reduction in certain of the monitoring programs by the Department of Environmental Quality (DEQ). The revised annual study program was to be continued with a review every three years for possible revisions or changes. This report represents findings from monitoring programs conducted during 2000, the third year of the three year study period and a review of the 1998-2000 data.

Station generation for 2000 was again outstanding with levels reaching the highest yearly average for capacity since 1978 when the station began commercial operation. Water temperature and fish community data for 2000 both in the lake and downstream were similar to historical data.

For example, numbers of fish collected in lake electrofishing surveys in 2000 were similar to 1999 and within the historical ranges. It was theorized that low lake levels in 1998 concentrated bluegill sunfish Lepomis macrochirus at several sample sites resulting in the relatively large numbers of fish collected that year. The sampling for 2000 occurred at or near normal lake level. Numbers of fish collected by gill netting in 2000 were higher than in 1999 but similar to historical data. In 2000, Lake Anna anglers reported 72 citation largemouth bass Micropterus salmoides (greater than 55.9 cm in length or 3.6 kg in weight) ranking Lake Anna as the third best trophy bass lake in the state.

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The 2000 hydrilla Hydrilla verticillata survey indicated a decrease in acreage both in the lake and Waste Heat Treatment Facility (WHTF) when compared to 1999 totals. Further, hydrilla in both the lake and WHTF was represented by plants 10 to 20 cm in length with limited vertical shoots and minimal biomass.

In the lower North Anna River, the total number of fish collected by electrofishing in 2000 decreased relative to 1999 at all four sampling stations and were in the lower range of totals reported for the period 1981-2000, most likely due to a missed survey in September of 2000. Underwater observations of largemouth bass and smallmouth bass in 2000 again showed largemouth bass to be more abundant in the upper reaches of the river below Lake Anna with smallmouth bass more abundant in the lower reaches.

In summary, the data indicate that the lake and river downstream of the lake continue to support diverse and healthy fisheries.

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List of Figures Figure Page Number Title 2.0-1 1998-2000 North Anna Units 1 & 2 Daily Pow er Level.....................................................................................................

26 3.1-1 Approximate location of fixed Endeco and Onset temperature recorders in Lake Anna and WHTF...........................................

27 3.1-2 Approximate location of thermal plume sampling stations on Lake Anna.....................................................................................

28 3.1-3 Upper Lake seasonal temperature patterns, Lake Anna Station NAL719ST (1998-2000)...................................................................

29 3.1-4 Mid-Lake seasonal temperature patterns, Lake Anna Station NAL208T (1998-2000).......................................................................

30 3.1-5 Lower lake seasonal temperature patterns, Lake Anna Station NALST1 0 (1998-2000)...........................................................

31 3.2-1 Location of Gill Netting stations on Lake Anna and W H TF.......................................................................................................

32 3.2-2 Lake Anna Gill Net data (1990-2000) average number and average weight (kg).......................................................

3.....

3 3.2-3 Catch per unit effort electrofish and gill netting in Lake Anna (1990-2000)..........................................................

34 3.3-1 Approximate locations of Electrofish stations on Lake Anna and W H TF...........................................................................................................

35 3.3-2 Lake Anna Electrofish data (1990-2000) average number and average weight (kg).......................................................

36 3.3-3 Composition of LMB catch Lake Anna and WLCHTF (1998-2000).......................................................................................

37 3.3-4 Composition of Bluegill catch in Lake Anna and W HTF (1998-2000)................................................................................

38 3.4-1 Lake Anna above Route 208 Bridge indicating hydrilla in 2000..............................................................................

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List of Figures (cont.

Figure Number Title Page 3.4-2 Lake Anna below Route 208 Bridge indicating hydrilla during 2000.......................................................................

40 3.4-3 Lake Anna Lagoon 1 indicating hydrilla beds in 2000.................................................................................................................

4 1 3.4-4 Lake Anna Lagoon 2 indicating hydrilla beds in 2000.................................................................................................................

42 3.4-5 Lake Anna Lagoon 3 indicating hydrilla in 2000.................................................................................................................

43 3.4-6 Acres of Hydrilla colonization in Lake Anna and the WHTF for the period (1991-2000)............................................................

44 4.1-1 Location of North Anna River temperature recording, electrofishing, and snorkel survey stations................................................................................................

45 4.2-1 North Anna River mean monthly streamflows 1980-2000............................ 46 4.3-1 Number of fish collected annually from the North Anna River during electrofishing surveys, 1981 -2000.....................................................................................................

47 4.4-1 NAR-1 smallmouth and largemouth bass median densities, and mean visibility, 1987-2000..........................................

48 4.4-2 NAR-2 smallmouth and largemouth bass median densities and mean visibility, 1987-2000..........................................

49 4.4-3 NAR-4 smallmouth and largemouth bass median densities, and mean visibility, 1987-2000..........................................

50 4.4-4 NAR-5 smallmouth and largemouth bass median densities, and mean visibility, 1987-2000.........................................

51 I

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List of Tables Table Number Title Pae 2.0-1 Seasonal summary of North Anna Power Station operation (percent of total station load) 1978-2000...................................................................................

52 3.1-1 Summary of North Anna fixed recorder temperature data during 2000. Values are means of daily high, mean and low temperatures (in degrees celsius). All instruments are located at the surface except for NALST10 which is at m id-depth.....................................................................................................

53 3.1-2 North Anna Lake Survey showing temperatures (in Celsius degrees) measured at one meter interval depths for stations in Lake Anna...................................................................

56 3.2-1 Surface water temperature (C), conductivity (umhos),

pH (standard units) and dissolved oxygen (mg/1) recorded at time of sampling during 2000.....................................................

60 3.2-2 Fishes collected in Lake Anna and the WHTF by gill netting in 2000....................................................................................

61 3.2-3 Number and weight (g) of fishes by station collected by gill netting at Lake Anna during 2000.......................................

62 3.2-4 Gill Net Summary for 2000............................................................................

63 3.3-1 Fishes collected in Lake Anna and W IHTF by electrofishing in 2000................................................................................

64 3.3-2 Number and weight (g) of fishes by station collected by electrofishing at Lake Anna during 2000...................................

65 3.3-3 Electrofishing Summ ary 2000.............................................................................

66 3.4-1 Estimate of Hydrilla verticillata colonization of Lake Anna and WHTF North Anna Power Station, 2000.......................................................................................

67 V

List of Tables (cont.)

Table Number Title Page 4.1-1 Mean, maximum, and minimum hourly water temperatures (C) recorded in the North Anna River, at station NAR-l by month, during 2000.

Sample size (n) equals the number of hourly Observations recorded each month................................................................

68 4.3-1 Number and biomass (g) of fishes collected during May, August and September 2000 electrofishing surveys of the North Anna River............................................

69 4.3-2 Raw catches of fish by gear type in the North Anna River for the period 1990-2000.....................................................................

70 4.3-3 Fishes collected from the North Anna River during annual electrofishing surveys, 1981-2000.....................................................

71 4.3-4 Ranked abundance of species comprising greater than 80 percent of the pooled annual North Anna River electrofishing catch from all station, 1981-2000............................................

72 4.3-5 Station total numbers and weights for 1998-2000 in the N orth A nna River.....................................................................................

73 4.4-1 Number of smallmouth bass and largemouth bass observed during North Anna River snorkel surveys conducted in 2000. Sample size (n) equals the number of times each count was performed in 2000...................................................

74 4.4-2 Cover use by smallmouth bass and largemouth bass in the North Anna River observed during the first of three counts made during snorkel surveys conducted in 2000..............................................................................

75 4.4-3 Cover use by smallmouth bass and largemouth bass in the North Anna River observed during the first of three counts made during snorkel surveys conducted in 2000. Data for observations at all stations are pooled.........................................................................................

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1.0 Introduction In 1972, the North Anna River was impounded to create Lake Anna, a 3885 hectare (9600 acres) reservoir (lake) that provides condenser cooling water for the North Anna Power Station (NAPS). Adjacent to Lake Anna is a 1376 hectare (3400 acre) Waste Heat Treatment Facility (WHTF) that receives the cooling water and transfers excess heat from the water to the atmosphere before discharging into the lake.

Aquatic monitoring studies have been conducted on Lake Anna since its inception.

In January, 1984, the Company initiated an extensive Section 316(a) demonstration study (P.L.95-500) to determine if proposed effluent limitations on thermal discharges from the power station were more stringent than 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 appreciable harm to the biological community. The Virginia Water Control Board (VWCB) accepted the study as a successful demonstration in September, 1986.

Subsequent to the 316(a) study, the Company committed with the VWCB to continue environmental monitoring on Lake Anna and the lower North Anna River as part of a post 316(a) agreement. Also, following each three year period of data collection, a summary report is provided with recommendations for future studies. This report presents the findings for calendar year 2000, and a review of the three year period 1998-2000.

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2.0 Station Operation North Anna Power Station (NAPS) operated at an average of 94% of capacity for 2000. This represents the highest yearly average for the station since it began commercial operation in 1978. The station operated at 84% and 91% of capacity for the first quarter and second quarter respectively and 100% for the third and fourth quarter. The Station's Unit 1 was shutdown in March for a scheduled refueling outage after completing a record run of 522 days on line. This outage resulted in the lower capacity during the first and second quarter. There were two other short station outages during this period (Table 2.0-1). An average of 91% capacity for the period 1998-2000 represents the highest three year percentage since the station began operation allowing NAPS to continue as an industry leader in low cost generation.

3.0 Lake Anna 3.1 Temperature Methods Lake water temperature data in 2000 were collected using continuous monitors (fixed temperature recorders) and instantaneous field surveys. Continuous temperatures were measured using Endeco model 1144SSM and Onset Optical Stowaway temperature recorders which measure and record the water temperature at one hour intervals at seven (7) stations in the lake and three (3) stations in the WHTF. These instruments were located one meter below the lake surface at the stations depicted in Figure 3.1-1, the lone exception being I 2

Station NALST10. The instrument at this station was located at a depth of three meters to account for the turbulence associated with mixing. A summary of the data recorded by these instruments for 2000 is presented in Table 3.1-1 as monthly means of daily high, mean and low temperatures.

The instantaneous temperatures were measured using a Yellow Springs Model 3000 T-L-C field temperature instrument. Temperatures were measured quarterly at one (1) meter intervals, surface to bottom, at the stations shown in Table 3.1-2.

Results The maximum monthly mean of daily high temperatures recorded for the lake in 2000 by continuous monitors was 29.8°C in July at Station NALBRPTT which is located at mid-lake (Table 3.1-1). The lowest monthly mean of daily low temperature recorded x\\.&

4.4°C in December at Station NAL719NT which is located on the Pamunkey arm of the upper lake. These 2000 high and low temperatures as well as the rest of the month]x temperature data in Table 3.1-1 are within the ranges of data reported in previous years.

The instantaneous temperature surveys were conducted quarterly to provide temperature data to assess seasonal thermal stratification patterns in the lake. Temperatures recorded in the third quarter and fourth quarter showed little stratification (Table 3.1-2).

During these surveys, surface to bottom temperature differences rarely exceed 2°C in the middle and upper reaches of Lake Anna. The July survey results show a thermocline at the 9 to 10 meter depth in the lower lake which was not present in the more shallow, upper portion of the lake. This stratification pattern in the lake is not unusual and is similar to previously reported patterns (Virginia Power 1986-1999).

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Temperatures recorded in the upper, middle and lower portions of the lake for the three year period 1998-2000 were similar in both range and seasonal pattern. This is demonstrated graphically for Station NAP719ST, an upper lake location on the North Anna Arm; NAL208T, a mid-lake station; and Station NALT10, located in the lower lake at Dike 3; in Figures 3.1-3, 3.1-4 and 3.1-5, respectively. These seasonal patterns for temperature in Lake Anna are consistent with previously reported data (Virginia Power, 1997).

3.2 Fish Population Studies - Gill Nettin2 Methods The monitoring of fish assemblage abundance and species composition for Lake Anna and the WHTF continued in 2000 using the same basic sampling technologies applied since 1972. Experimental gill netting was used to capture fishes which normally inhabit the deeper strata of the lake, or exhibit a diel movement to and from the shoreline. Similar to previous years, 2000 gill net surveys were conducted during February, May, August, and October at the stations shown in Figure 3.2-1. Experimental gill nets were set near littoral drop-off areas with procedures remaining unchanged since 1972. Fish collected by gill netting were returned to the laboratory where all individuals were measured to the nearest millimeter total length and weighed to the nearest 0.1 gram. Surface water temperature (°C),

dissolved oxygen (mg/1), pH and conductivity ((rmhos) were recorded at the time of each sample collection (Table 3.2-1).

Results Sixteen (16) species of fish representing seven (7) families were collected in Lake Anna and the WHTF by quarterly gill netting in 2000 (Table 3.2-2). A total of 710 fish 4

weighing 288.0 kg was collected from four stations in the lake and two stations in the WHTF (Table 3.2-3). The 2000 total (710) was higher than 1999 (670) but lower than 1998 (817),

while gill net biomass in 2000 (288.0 kg) was lower than biomass totals in both 1999 (296.47 kg) and 1998 (360.8 kg). Of the 710 fish collected, 535 (210.1 kg) were collected in the lake and 175 (77.9 kg) were collected in the WHTF. The February survey yielded the greatest number and total weight of fish collected representing 31% of the total number of all fish collected and 38% of the total weight of all fish collected, from all stations combined.

Table 3.2-3 also includes the average number and weight of fish collected per net set for each station for comparison of catch per unit effort by number (CPUE-N) and weight (CPUE-W). CPUE-N for all stations combined in 2000 was 29.6 fish per net while CPUE-W was 12.0 kg per net. These values are compared to CPUE in previous years in Figure 3.2-2.

Over the last 10 years, CPUE-N has ranged from 42 to 28 with a mean of 30, while CPUE W has ranged from 16 kg to 12 kg with a mean of 14 kg. Figure 3.2-2 also indicates that the size of fish collected by gill net has increased in recent years (1995-2000) because CPUE-N has decreased during this period while CPUE-W has remained high.

When the catch per unit effort is compared among stations in 2000, CPUE-N ranged from a low of 17.3 fish per net at the Lagoon 3 Station to a high of 74.0 fish per net at the North Anna Arm Station (Table 3.2-3). Likewise, CPUE-W ranged from a low of 6.3 kg per net at the Lagoon 3 Station to a high of 20.6 kg at the North Anna Arm Station. This is consistent with past data.

Table 3.2-4 presents the relative percentages of species collected in terms of numbers and weights by gill netting in 2000. The numerically dominant species collected in the lake was gizzard shad Dorosoma cepedianum, followed by striped bass Morone saxatilis, black 5

crappie Pomoxis nigromaculatus and white perch Morone americana. These results are similar to data collected in 1999 and 1998 and are also consistent with other years. The dominant species in the lake relative to biomass was striped bass followed by gizzard shad and channel catfish Ictalurus punctatus.

The numerically dominant species collected in the WHTF in 2000 was also gizzard shad, followed by channel catfish, white catfish Ameriurus catus and white perch. The weight-dominant species in the WIHTF in 2000 was common carp Cyprinus carpio followed by gizzard shad, channel catfish and white catfish.

Due to their relatively high numbers, gizzard shad have generally ranked high in biomass catch in both the lake and WHTF. The larger but less abundant channel catfish, common carp and white catfish have consistently ranked high in biomass in both places with annual ranking depending on the variation in catch.

Striped bass, have consistently comprised a large portion of the biomass in the lake but not in the WHTF.

3.3 Fish Population Studies - Electrofishing Methods Boat electrofishing was used in 2000 to evaluate the assemblage and abundance of fish populations which normally occupy the shoreline habitat. The techniques, stations, and frequency have remained virtually unchanged since 1972. Sampling was performed in February, June, August, and November at the stations identified in Figure 3.2-1. Each station is 100 meters in length and normally includes a brush pile except for the dike stations which are comprised of uniform rip-rap.

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All fish collected were either returned to the laboratory for processing or released in the field, e.g., larger game fish were measured, weighed, and released. In the laboratory, at least twenty-five (25) individuals per species from each station were measured to the nearest millimeter total length and weighed to the nearest 0.1 gram. Those individuals over twenty five (25) per species were enumerated and bulk weighed. Surface water temperature (°C),

dissolved oxygen (mg/1), pH and conductivity (4mhos) were recorded at the time of each sample collection (Table 3.2-1).

Results Twenty-one (21) species of fish representing eight (8) families were collected by electrofishing operations in the lake and WHTF in 2000 (Table 3.3-1). A total of 5,226 fish weighing 105.4 kg was collected from the five stations in the lake and the four stations in the WHTF during the 2000 sampling period. The total number of fish collected in 2000 (5,226) approximated the total number collected in 1999 (5,277) and was lower than the total in 1998 (6,991). Electrofishing biomass in 2000 (105.4 kg) was lower than that of 1999 (106.9 kg) as well as 1998 (83.1 kg). In 1998, Lake Anna fell to 2.6 feet below normal pool for an extended period dewatering much of the shallow shoreline fish habitat. It is thought that small fishes may have migrated to the rip-rap dike habitat as shoreline habitat declined during this period thereby inflating electrofishing totals.

Of the 5,226 fish collected in 2000, 2,476 (72.6 kg) were collected from the lake and 2,750 (32.8 kg) were collected from the WHTF (Table 3.3-2). When the data are compared seasonally, the 2000 electrofishing results are similar to previous years with the greatest numbers of fish being collected in the winter (February - 1,610 individuals) and fall (October 7

- 2,381 individuals) surveys. Typically, in the fall, recruitment of the young-of-year (YOY),

plus the return of fish to shallow water as the weather moderates generally increases the number of fish available to collection by shoreline electrofishing.

Table 3.2-2 also includes the average number and weight of fish collected per electrofishing sample for each station for comparison of catch per unit effort by number (CPUE-N) and weight (CPUE-W). CPUE-N for all stations combined in 2000 was 145 fish per sample while CPUE-W was 30 kg per sample. These values are compared to CPUE in previous years Figure 3.3-2. Over the last 10 years, CPUE-N has ranged from 112 to 194 with a mean of 127, while CPUE-W has ranged from 28 kg to 41 kg with a mean of 33.9 kg.

CPUE-N in 2000 was consistent with most previous surveys with the exception of 1998 when large numbers of small fishes were concentrated on the dike stations as discussed previously. CPUE-W was above average in 2000 and within the range of previous biomass I estimates. It is interesting to note that biomass decreased in 1998 when fish numbers increased reflecting the relatively high numbers of small fish concentrated at dike stations that year.

When the catch per unit effort for each electrofishing station in 2000 are compared, CPUE-N ranged from a low of 56 fish per sample at the North Anna Arm Station to a high of 379 fish per sample at the Dike I - WHTF Station (Table 3.3-3). CPUE-W ranged from a low of 0.7 kg per sample at the Lagoon 3 Station consisting of mostly small bluegill to a high of 7.6 kg at the North Anna Arm Station (primarily due to the capture of the larger common carp at this station).

The numerically dominant species collected in both the lake and WHTF by boat electrofishing in 2000 was the bluegill sunfish (Table 3.3). Bluegill sunfish ranked first in 8

weight in the WHTF, followed by largemouth bass. In the lake, largemouth bass ranked first in weight followed by common carp and bluegill sunfish. These results are similar to those of 1999 and 1998 as well as those in the historical records.

When lake gill netting and electrofishing data for selected species are combined and examined for size class distribution, the data indicate certain population trends. Similar to 1998 and 1999, young-of-year (YOY) was the predominant size class of largemouth bass in 2000 although all the three size classes were well represented each year (Figure 3.3-3).

Fewer YOY and intermediate size bass were collected in 2000 than in 1998 and 1999, while more harvestable bass were caught. Figure 3.3-4 demonstrates a decrease in the relative abundance of the YOY class and an increase in the relative abundance of intermediate and harvestable size classes from 1998 to 2000.

Lake Anna ranked third among bodies in the State of Virginia for largemouth bass citations with 72 being reported in 2000. A citation for largemouth bass is awarded for fish greater than 55.9 cm in length of 3.6 kg in weight. The lake was also third in black crappie citations as well with 26 being reported in 2000 (greater than 38.1 cm in length of 0.91 kg in weight).

Overall, the data for gillnetting and electrofishing in 1998-2000 reveal no major changes in the lake ecosystem when compared to past data. Lake Anna continues to support a healthy, well-balanced biological community.

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3.4 Aquatic Vegetation Methods Hydrilla is an exotic, submerged, aquatic macrophyte which, in most bodies of water, has the ability to grow and spread rapidly. The primary method of reproduction is by fragmentation. Hydrilla also produces overwintering structures in two (2) separate areas of the plant: tubers, produced by the roots in the hydrosoil; and turions, formed at the leaf axils of the plant. Each has the ability to produce new plants at the beginning of each new growing season.

An annual aerial survey is conducted to map hydrilla growth in Lake Anna. The 2000 survey of Lake Anna was conducted in late November. The survey is conducted by helicopter with personnel from VDGIF and the Company. The entire shoreline of the lake and WHTF is surveyed to document areas of hydrilla colonization. The locations of I observed hydrilla are marked on a topographic map of Lake Anna and returned to the laboratory for computerization. The computerization of the data allows the acreage of hydrilla to be calculated, and also production of maps indicating the location of the hydrilla.

Results Acres of hydrilla colonization of Lake Anna and the WHTF in 2000 are mapped in Figures 3.4-1 through 3.4-5. Hydrilla acreage decreased in Lake Anna proper from 113 acres in 1999 to 94 acres in 2000. A decrease was noted in the WHTF from 35.5 acres in 1999 to 29 in 2000. The totals for 2000 are the lowest since 1995, the year after sterile grass carp were stocked by Dominion in the WHTF.

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The amount of habitat available for hydrilla colonization in the lake and WHTF is estimated in Table 3.4-1 as the acreage of reservoir bottom with 15 feet or less water depth.

The acreage of actual hydrilla coverage in 2000 is also presented so that a percentage of available habitat that is currently present (29 acres) can be calculated. In 2000 only 2% of habitat available to hydrilla was actually colonized in both the lake and WHTF. This continues a general decline in total acreage for the lake and WHTF since 1995. The sudden drop in acreage in 1995 is probably the result of grass carp stocking and also adverse weather conditions which greatly increased the turbidity in the lake during the growing season that year.

Not only has the total acreage of hydrilla colonization decreased but also the nature of the plant itself. The hydrilla plants in 2000 generally consisted of short, stunted plants with minimal vertical growth and biomass production. This has been the growth pattern since grass carp were stocked and is attributable to carp grazing on the plants.

To assess the effectiveness of hydrilla control by the grass carp, exclusion areas were established in 1995 in the WHTF and 1997 in the lake. Exclusion areas are 10 foot by 10 foot square fenced areas which prevent grass carp from feeding on the hydrilla inside. The low lake level in 1998 resulted in dewatering the exclusion area in the WHTF thereby rendering it ineffective for hydrilla growth evaluation. This dewatering also affected the exclusion areas in 2000. Because of the low water hydrilla was present in only three of the six exclusion areas, two in the main lake and one in the WIHTF. Historically, the exclusion areas have exhibited hydrilla growth inside the fenced area while the area around them has been devoid of hydrilla plants. This pattern of growth within the protected areas in the three 11

I areas in 2000 continued and is consistent with the literature in other lakes where grass carp have been stocked (Webb, et al, 1994).

One observation that can be made regarding the continued decrease of acreage of hydrilla in 2000 is that atypical weather conditions which interfered with hydrilla growth in 1998, and perhaps continued into 1999, combined with the sterile grass carp seem to be producing the desired and predicted results, i.e., control of the growth and biomass without eliminating hydrilla totally from the ecosystem of the lake.

3.5 Conclusions North Anna Power Station in 2000 operated at the highest generation levels since 1978 when commercial operations began. The three year period of 1998-2000 also produced the highest average generation level since 1978.

The 2000 water temperature data from the continuous recorders indicated water temperatures within the ranges of data from previous years.

Thermal stratification patterns measured in 2000 indicated similar stratification patterns to those in 1998 and 1999 and followed closely previously reported data.

Gill netting and electrofishing data showed little change in the abundance of fishes and the taxonomic composition of the fish population during 1998 through 2000.

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0 Based on numbers of citation largemouth bass and black crappie reported by anglers, Lake Anna ranked as the third best trophy lake for both largemouth bass and black crappie in the state for the period 1998-2000.

0 Overall hydrilla acreage for 2000 decreased in the lake and WHTF with the hydrilla plants being 10 to 20 cm in length and thereby producing limited biomass. The overall acreage of hydrilla decreased during the period 1998-2000.

3.6 Recommendations o

Continue the biological monitoring of Lake Anna and the WHTF at its present level.

o Reduce the lake temperature surveys to twice a year. The data collected continues to show consistent thermal patterns which have been historically reported. Reducing the surveys to twice a year will have no adverse effect on the environmental monitoring of Lake Anna and will fully meet the permit requirements.

4.0 North Anna River 4.1 Temperature Methods Water temperatures (CC) were recorded hourly at station NAR-1 in the lower North Anna River during 2000 (Figure 4.1-1) using an Onset temperature recorder. This instrument 13

has an accuracy range of +/-0.50C. Station NAR-1 is located approximately 1 km below the Lake Anna dam.

Results and Discussions Water temperatures for 2000 were highest from June through September with mean monthly water temperatures 27TC (Table 4.1-1). A maximum temperature of 31.20C was recorded at NAR-1 in July and again in August 2000. Historically, maximum water temperatures have occurred in July or August.

A minimum temperature of 5.4' C was recorded at NAR-1 in January 2000.

4.2 River Flow Methods River discharge (cfs) data were obtained from the United States Geological Survey (USGS) to document the timing and magnitude of hydrologic events. These events, along with water temperature, are among the most important abiotic factors affecting the abundance and distribution of stream organisms. Data were obtained from USGS gaging station 01671020 (Hart's Corner) near Doswell, Virginia.

The station is located approximately 37 km downstream of the Lake Anna dam at NAR-6 (Figure 4.1-1).

Results and Discussion The pattern of seasonal flows in the North Anna River has generally been characterized by high flows in the winter and spring, reduced flows during summer, and lower flows during late summer and early autumn. This is a pattern commonly exhibited by 14

many rivers draining the eastern United States, and is generally reflective of annual rainfall patterns.

In 2000, North Anna River flows for the period January - March were below the 1998-2000 average with mean monthly flows between 200 and 400 cfs (Figure 4.2-1).

Typical of historical patterns, flows generally decrease from April through June. This pattern was exhibited in 2000 with the exception of increases due to sporadic rain events in mid and late April when flows ranged from 1200 - 2300 cfs. The maximum daily mean recorded in 2000 was 2350 cfs on April 18 and was associated with a short-term rain event. Mean daily flows rarely exceeded 100 cfs in July, August and September and 79% of the daily mean values calculated for this period were below 100 cfs.

The historical flow patterns for the period from 1980-2000 indicate that summer and fall river flows are moderately low. A comparison with the 2000 flows for this same period demonstrates exacerbated low mean flows indicative of ongoing drought conditions.

4.3 Fish Population Studies-Electrofishing Methods Abundance and species composition data for the North Anna River fish assemblage in 2000 were collected during electrofishing surveys. Consistent sampling techniques have been used in all North Anna River electrofishing surveys since 1981.

An approximately 70-m reach of riffle/run type habitat is sampled at each station with an electric seine (Virginia Power 1986). Prior to sampling, each reach is blocked at the downstream ends with a 6.5-mm mesh net. Sampling is conducted by working the electric seine from bank to bank in a zigzag pattern from the upstream to the downstream end of the 15

I section. Nearby pool type habitats are then sampled for 10 minutes of effort with a backpack electrofisher. Fish sampled by electric seine and backpack electrofisher were collected using 6.5-mm mesh dip nets.

Most fish collected are preserved in 10% formalin and transported to the laboratory for appropriate processing. Some larger fish are weighed and measured in the field and released. In the laboratory, a maximum of 15 individual specimens of each species is weighed to the nearest 0.1 g and measured to the nearest one (1) mm total length (TL). If more than 15 specimens of a species are collected, those in excess of 15 are counted and weighed in bulk. Electric seine and backpack electrofisher collections are then pooled by station and survey month for analyses.

Sample frequency for electrofishing is typically once per month each year in May, July and September.

In 2000, electrofishing surveys on the North Anna River were I conducted in May, July, and September. It was necessary to delay the July electrofishing survey until August due to a rain event.

Results and Discussion A total of 688 fish was collected from the North Anna River during electrofishing surveys conducted in 2000 (Table 4.3-1). This compares to a total of 2,258 fish in 1999.

Electric-seine collections were not made in September, 2000 due to high river flows; however, backpack electrofishing was conducted at each of the four sites. Attempts were made to reschedule the survey but either weather conditions or available manpower were problematic. Calculated estimates were made to determine the effect of the missed portions of September 2000 survey on the overall catch for the year.

16

The average number of fish collected by electric-seine during September for the 10 year period is 448 (Table 4.3-2).

This number was obtained by adding all of the totals for September electric-seine collections and dividing the total by ten which is the number of years sampled. This average number of 448 then represents an average of what was missed by not doing the September collections. Adding this "missing average" to the known total of 688 equals a new total of 1,136.

Complete sets of numbers are available for the years of 1990, 1991, 1992, 1993, 1997, 1998 and 1999 (Table 4.3-2). The adjusted number for 2000 of 1,136 compares to the other years for which complete data sets are available as being in the lower 1/3 of the data set. When comparing all years graphically (Figure 4.3-1) it becomes very apparent that the years in which there are missed samples represent the lowest years for total fish collected.

The 2000 collection includes 23 species and seven (7) families (Table 4.3-3). Over the past 18 years, 49 species of fish have been collected from the North Anna River with annual totals ranging from 18 to 32 species.

A common characteristic of stream systems is the tendency for a few species to numerically dominate the stream fish assemblage (Matthews 1982). Six (6) to 10 species have accounted for greater than 80 percent of the North Anna River electrofishing catch from all stations in any year since sampling began in a consistent manner in 1981 (Table 4.3-4).

This trend continued in 2000 with 6 species accounting for greater than 80 percent of all fish collected. These species were, in decreasing order by numbers, redbreast sunfish Lepomis auritus, satinfm shiner Cyprinella analostana, redfm shiner Lythrurus ardens, american eel Anguilla rostrate, margined madtom Noturus insignis, fallfish Semotilis corporalis and shield 17

darter Percina peltata. These species have consistently been among the most abundant species collected from the North Anna River since 1981.

Table 4.3-5 indicates that in 2000, irrespective of missing samples, station NAR-1 yielded the greatest numerical catch followed by, in decreasing order, NAR-4, NAR-6 and NAT-2. In terms of biomass (total weight) in 2000, NAR-1 ranked first followed by NAR-2, NAR-6 and NAR-4.

This numbers ranking in 2000 compares to 1998 and 1999 when NAR-2 yielded the most fish collected. Biomass for all three (3) years is greatest at NAR-1 probably attributable to numbers of the larger centrachids and eels collected at NAR-1 when compared to the other stations.

Past surveys have indicated that high winter and spring flows often result in decreased North Anna River catches. In 1993, the relationships between flow and annual fish abundance were examined. Based on the results of Spearman's correlation analysis (Hollander and Wolf 1973), low late winter/early spring flows tend to be conducive to relatively high electrofishing catches later in the year, and conversely, the high flows early in the year tend to result in low electrofishing catches (Virginia Power, 1994). This may have contributed somewhat to the lower numbers of fishes collected in 2000 when early spring flows were near the normal high flow conditions for the twenty year period 1980 2000.

18 I

4.4 Fish Population Studies-Direct Observation Methods To further amplify and understand fish population studies in the North Anna River, abundance and distribution data for smallmouth bass Micropterus dolomieu and largemouth bass were gathered via direct observation using snorkel surveys. Consistent observation techniques have been used in snorkel surveys since 1987 with some variation in sampling frequency at some stations among years due to instances of high river flow conditions, electrical storms, etc.

In 2000, snorkel surveys were conducted during July, August, and September. Four (4) stations were sampled twice per month in August and September; NAR-1, NAR-2, NAR 4, and NAR-5 (Figure 4.1-1). Primarily due to a relocation of our laboratory in July of 2000 as well as the planning, etc., associated with the move, only one survey was conducted in July as opposed to the normal two (2) surveys.

Abundance estimation procedures were identical to those employed since 1987 (Virginia Power 1988). Counts of smallmouth bass (SMB) and largemouth bass (LMB) were made while swimming 100 m transects along the north and south banks of each station.

Transects followed an approximately one meter depth contour.

All bass sighted were categorized by species as to young-of-year (YOY) (<.120 mm),

stock-size (120<SMB<280 mm or 120<LMB<305 mm), or quality-size (SMB>280 mm or LMB>305 mm). In addition to size group, all bass sighted were categorized as to type of cover being used; bedrock ledge (Ledge), boulders (Boulder), instream woody debris (Wood), aquatic vegetation (Vegetation), or no apparent cover use (Open). Fish had to be within 0.5 m of a cover object at the moment of sighting to be included in a cover use 19

I category other than the Open category. Aquatic vegetation was included as a cover type beginning in 1993 due to annual increases in the amount of vegetation observed from 1990 through 1992, and apparent associated increase use by fish.

During each survey, three successive counts at each station were made at each bankside transect. Each observer made an independent estimate of the distance that YOY smallmouth bass (TL<120 mm) could be distinguished from YOY largemouth bass (TL<120 mm) at each station. Lateral visibility at each station was estimated by averaging the independent estimates of both observers. Counts of smallmouth bass and largemouth bass were converted to density estimates (number/hectare of bankside channel) to account for differences in average visibility among survey days and sampling stations. Density estimates for all smallmouth bass and largemouth bass larger than YOY size were pooled by species, station, and sample year to facilitate identification of species-specific and station-specific I changes over time. Calculations of median density estimates by sample year and associated 95% confidence intervals were based on Walsh averages (Hollander and Wolfe 1973). YOY densities were not calculated as it was doubtful that YOY were as susceptible to the observation technique as were larger fish, due primarily to their small size and cryptic nature.

Cover utilization data from the first of three sets of observations obtained during each snorkel survey were used to examine differences in cover use by smallmouth bass and largemouth bass. Data from only the first count were used because it was assumed fish observed during the first count would be relatively undisturbed by divers, whereas fish observed on the second and third counts may have changed their positions in response to divers passing by during the first count.

20

Results and Discussion Snorkel surveys for 2000 were conducted between 0830 and 1429 hours0.0165 days <br />0.397 hours <br />0.00236 weeks <br />5.437345e-4 months <br /> at river temperatures ranging from 14.7 to 28.80C and average visibility ranging from 1.0 to 4.0 m.

Unlike previous years, when largemouth bass were the numerically dominant species observed at the upstream stations (NAR-1 and NAR-2), only at NAR-1 were largemouth the dominant species in 2000. Largemouth bass numbers observed at NAR-2 were similar to fish numbers observed at NAR-4 and NAR-5, the lower river stations where few largemouth bass are generally seen (Table 4.4-1).

Historically, largemouth bass have primarily dominated fish counts at the upper stations (NAR-1 and NAR-2) and smallmouth bass numbers have been greater at the lower stations (NAR-4 and NAR-5). However, in recent years, both species have occupied the entire study area. Variability between the north and south bank at any station appeared to be related to habitat complexity, i.e., fewer fish were observed along banks characterized by monotypic habitat than along banks with a variety of habitat types.

Density estimates for largemouth bass and smallmouth bass observed in 2000 for stations NAR-1, NAR-2, NAR-4 and NAR-5 are compared to historical density estimates in Figures 4.4-1 through 4.4-4. These estimates do not include young of year (YOY) size fish (TL# 120 mm) as it is doubtful that the smaller individuals are as susceptible to the observation techniques as are larger fish. In general, largemouth bass have been more abundant at the two uppermost stations (NAR-1 and NAR-2) than at the lowermost stations (NAR-4 and NAR-5), with the opposite evident for smallmouth bass. Largemouth bass densities at NAR-1 and NAR-2 averaged approximately 37 and 28 fish/hectare respectively over the study period, while densities at both NAR-4 and NAR-5 averaged approximately 21

I 7 fish/hectare. Conversely smallmouth bass densities averaged approximately 6 fish/hectare at NAR-1 and NAR-2 with average densities of 17 and 33 fish/hectare at NAR-4 and NAR-5 respectively. These trends have been evident during most but not all surveys. Densities calculated for 2000 decreased at all four stations (Figures 4.4-1 through 4.4-4). The most significant decrease was at NAR-4 (Figure 4.4-3) where largemouth and smallmouth bass median density values, previously 20 and 21.5 fish/hectare respectively in 1999 were zero for both species. Although largemouth and smallmouth bass are consistently observed at NAR-4 from year to year, their abundance appears more variable than at other stations. This has resulted in median density estimates of zero for largemouth bass occurring 7 of the 14 years of record (Figure 4.4-3). Smallmouth bass are generally more abundant, and density estimates higher, at NAR-4 with the exception of 1996 and 2000.

Hydrilla growth continues to pose problems for observers during the surveys. Low summer river flows and warmn water temperatures provide an excellent environment for growth of the nuisance aquatic plant. Consequently, each year, the use of the wood structure is being reduced due to the shoreline patches of hydrilla. Each station has either a north or south shoreline with its entire length being impacted by hydrilla that typically extends 6-10 feet out from the bank. Observations made during these runs are generally limited to the outer edge of the hydrilla and open water. Therefore, hydrilla is a factor that is reducing the ability of the observer to make accurate counts and is thereby contributing to the low median densities found in 2000.

Observations of cover use by smallmouth bass and largemouth bass are difficult to interpret without accounting for the availability of various cover types. For this reason, cover use data obtained in 2000 are primarily presented for documentation purposes (Table 4.4-2).

22

When cover use data are pooled for all stations in 2000 (Table 4.3-3) smallmouth bass were usually associated with wood, boulder, and open water while largemouth bass cover usage follows a trend witnessed in recent years. With recent increases in the abundance of aquatic vegetation in the lower North Anna River largemouth bass appear to be shifting from making nearly exclusive use of woody debris to dividing their use between woody debris and aquatic vegetation (Virginia Power 1996, 1997, 1998, 1999). Smallmouth bass have generally been evenly distributed between all cover types and this was again the case in 2000.

4.5 Conclusions 0

River flows were lower than normal throughout the year with the exception of several short-term rain or storm events. Mean daily flows in the summer of 2000 rarely exceeded 100 cfs with 79% of the daily means below 100 cfs.

0 Numbers of fish collected in 2000 by electrofishing decreased at all four stations and total numbers were more similar to 1989, 1993 and 1996. High spring flows and missed surveys contributed to low fish numbers.

0 Species composition of the 2000 North Anna River electrofishing catch was similar to previous years with six (6) species comprising 80% of the electrofishing catch in terms of numbers, and six (6) species comprising 83% of the electrofishing catch in terms of biomass.

23

I 0

Underwater observations of smallmouth bass and largemouth bass made in 2000 in the North Anna River from the dam to U.S. Route 1 indicated smallmouth bass were numerically dominant in the lower reaches of the river and largemouth bass were more abundant in the upper reaches. However, in recent years, smallmouth appear to be moving upstream and likewise, largemouth moving downstream.

Density estimates for both largemouth bass and smallmouth bass at all stations in 2000 were lower than average densities calculated for the entire study period. Dense hydrilla growth adjacent to shorelines is limiting the ability of observers to see and count fish and is thereby affecting numbers of observed fish.

Observations of cover use made in 2000 illustrate that smallmouth bass are often associated with boulder, wood, and vegetation and largemouth bass with wood or vegetation.

1998-2000 Studies Data presented in this report and previous reports indicate that the North Anna River below Lake Anna continues to support a diverse and stable fish assemblage. The taxonomic composition of the fish assemblage has been relatively stable from year to year, indicating power station effects are not evident in the North Anna River. The timing and magnitude of flood events appear to be the largest determinant factor governing fish abundance from year to year.

24

Further, the 1998-2000 data for the North Anna River continues to indicate that the river supports a mixed smallmouth and largemouth bass gamefish population. The historical trend of smallmouth bass being most abundant in the lower reaches and largemouth bass most abundant in the upper reaches may be in the process of changing. During the three year period of 1998-2000, more smallmouth bass have been seen in the upper reaches and more largemouth bass in the lower.

Comparative observations of cover usage of smallmouth bass and largemouth bass indicates that both species may segregate when choice of structure or cover is available. The overall preference for all size classes of both largemouth bass and smallmouth bass is wood and vegetation. Available wood habitat or cover is increasingly being lost due to growth and coverage of hydrilla.

Recommendations o

Over the last 10 years of monitoring, the fish assemblage of the North Anna River below Lake Anna has remained relatively stable and has been able to recover from natural occurrences such as flood events. However, because of the recent reduced flows as a result of ongoing drought conditions no changes in effort are proposed.

o Direct underwater observations for smallmouth bass and largemouth bass were initiated in 1987 to monitor species abundance, size, habitat preference and the expansion of their ranges. These observations should also continue at the current level of effort.

25

SI

_I JAN99 JANO0 M0NTH 1998-2000 NORTH ANNA UNITS 1 & 2 DAILY POWER LEVEL 100 90 70-

60.

50 40 30 20-JNI J AN9 8 JAN01

[GURE 2.0- 1.

Tý-

0t

FIGURE 3. i-1 Approximate location of fixed Endeco and Onset temperature recorders in Lake Anna and WHTF ORANGE CO.

N LAKE ANNA

'O,.S*

,NA1,7 1 9NT 2 KM NAI,208'r 2 Mile NAL719gST RI.

0 SPOTSYLVANIA CO.

"NA T.NT LOUISA CO.o CekNLN I*

NORTIHp EANNA N

IAIT111ST

/

~STATION I

NAlDISCI

/\\ashinggon.

D.C.Da 1

b1LakeI Anna Rk mand..VA o*=~.

A W

-S

-- IVUUill I lumill*a iu lnl rucIuIly NA4WIrIF2 NAWIITF3

FIGURE 3.1-2 Approximate location of thermal plume sampling stations on Lake Anna.

Nq 2

K M

FIGURE 3.1-3 Upper Lake seasonal temperature patterns, Lake Anna station NAL719ST(1998-2000) tJ

0 35 30 25 20 15 10 5

0

-1998

-1999 2000 jan feb mar april may june july aug sept oct nov dec col

FIGURE 3.1-4 Mid-Lake seasonal temperature patterns, Lake Anna station NAL208T(1998-2000) 4 jan feb mar april may june july aug sept oct nov dec l.a C

35 30 25 20 15 10 5

0 cm-

____1

FIGURE 3.1-5 Lower Lake seasonal temperature patterns, Lake Anna station NALST1 0(1998-2000) 35 30 25 20 15 10 5

0 jan feb mar april may june july aug sept oct nov Co0

-1998

-1999

-2000 dec

FIGURE 3.2-1 Location of Gill Netting stations on Lake Anna and WHTF ORANGE CO.

NORT, II ANNA ARMf LOUISA CO.

A Washington, D.C.

Lake Anna Richmond, VA N

LAKE ANNA 2 KM 2 Miles SPOTSYLVANIA CO.

HIURNIAN ISLAND) kNNA IN AGOON I LLVY CREEK Dam North I)ISCII*ARGIE -

.AKIE Z -

Waste Heat Treatment Facility 3

FIGURE 3.2-2 Gill Net data (1990-2000) average number and average weight (Kg) 18 16

-14 12 1 o

.)

NUMBER WEIGHT(Kg) 40 35 30

.LI

25 z

20 15 10 5

0 90 91 92 93 94 95 96 97 98 99 00 50 t5 6

4 2

0

FIGURE 3.2-3 Catch per unit effort Electrofish and Gill Netting in Lake Anna 1990-2000 94 95 96 97 250 200 150 100 50 0

-- ele

-u-gill

-L 91 92 93 98 99 00 90

FIGURE 3.3-1 Approximate locations of Electrofish stations on Lake Anna and WHTF ORANGE CO.

NORTH ANNA ARM LAKE ANNA 2 KM 2 Miles SPOTSYLVANIA CO.

THURMAN ISLAND kNNA R

rDIKE I-LAKE IN a.9'*

GOON I DIKE I-WtrF LOWER LAKE COVE-Washington, D.C.

Lake Anna Richmond, VA j-Waste Heat Treatment Facility

\\

DIKE 3 - LAKE DIE 3 - WHIT LAGOON 3 COVE N

LOUISA CO.

FIGURE 3.3-2 Lake Anna Electrofish data (1990-2000) average number and average weight (Kg)

--*--NUMBER - WEIGHT(Kg) 90 91 92 93 94 95 96 97 98 99 00 250 200 150 +/-

100 +

3

-2.5 I-,

-1.5

I.

50 0+

- 4.-,

1 10.5 0

I I

t

-L

-.-- 3.5

FIGURE 3.3-3 Composition of LMB catch in Lake Anna and WHTF (1998-2000) 60 50 40 U 1998

1999 U 2000 yoy<l 99 HAR har>300 int<300 cUt-30 20 10-0-

YOY INT Q

FIGURE 3.3-4 Composition of Bluegill catch in Lake Anna and WHTF (1998 - 2000) 60 U 1998 U 1999 5]2000 YOY < 76MM INT < 150MM HAR > 150 uJ 0

I-U0 z

uJ M.

50 40 30 20 10-0 YOY INT HAR CQS

FIt

,RE 3.4 - I Lake Anna above Route.

t mi I

A A

Af 0

j Bridge indicating hydrilla in 2000

/Owwý-

1%

r O

G0 U90A

FIc.*RE 3.4 - 2 Lake Anna below 208 Bk. -ge indicating hydrilla in 2000

£

,do rp I1 SI r

N'

.rI Li A 1.

Id r

Lt F

CO6, A

IL 0/

t IIL rF

FIGURE 3.4-3 LAKE ANNA LAGOON 1 INDICATING HYDRILLA BEDS IN 2000 C-07 41

FIGURE 3.4 - 4 Lake Anna Lagoon 2 indicating hydrilla beds in 2000 oco%

FkIURE 3.4 - 5 Lagoon 3 indiudting hydrilla in 2000

/

eo

FIGURE 3.4 - 6 Acres of Hydrilla colonization in Lake Anna and the WHTF for the period 1991-2000 LAKE WHTF Im91 *92 193 E194 E95 U96 U97 E398 E99 MOO-1000-

+/-*

V, 500 04

_0

FIGURE 4.1-1 Location of North Anna River temperature recording, electrofishing, and snorkel survey stations.

Spotsylvanla County N

Louisa County Caroline County nI. 738 I tanover Co.

Noel I lanover Co.

(NAR-5) 4t-A To Fredericksburg fI. 1 Hanover Co (NAR-6)

Fit. 667 Hanover Co.

0 2

4 Kilometers

,t Fit. 54 I Hanover Co.

RI. 33 I Hanover Co.

To Richmond I

Hanover County Miles 0 2

Figure 4.2-1 North Anna River Mean Monthly Streamf lows 1980- 2000 I--- 1980-2000 Monthly Means --! 2000 Monthly Means

._7_

900 800 700 600 500 400 300 200 100 0

Jan Feb Mar Apr May Jun Jul Month Aug Sep Oct Nov Dec

(

IL CU U)

+

I I

l

Figure 4.3-1. Number of fish collected annually from the North Anna River during electrofishing surveys, 1981-2000.

1200 4l00 3500 1000 3000 8a0 600 400 200 2oo 2500 E

1500 E

1000 500 0

1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 199 1994 19 1M 1997 19N 1999 2000 0

Year of Coleclion NAP-i -4 NAR-2 ----

NAR-4 A--NAR-6 M--AM Statons "06 z

C-il

Figure 4.4-1. NAR-1 smallmouth and largemouth bass median densities, and mean visibility, 1987-2000.

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year L..

90 80 70 60 50 40 30 20 10 0

3.5 3

2.5 1.5 >

1 0.5 0

[--m-SMB - o*LMB --*'-Visibility,

Figure 4. 4-2. NAR-2 smallmouth and largemouth bass median densities, and mean visibilities, 1987-2000.

5

-- 2.5 45 3

~..4 0 2

M E 25-"B 1.5 >

S 20 "1510 5

10-0.5 0-

)0 1 987 1988 1989 1990 991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year I=-sB

--*- LMB -*-aVisibli ty

Figure 4. 4-3. NAR-4 smallmouth and largemouth bass median densities, and mean visibilities, 1987-2000.

60 50 0

I(U U

0 I

C)

.0 E C

(0 C

0 0 40 30 20 10 0

3.5 3

2.5 1.5 >

1 0.5 0

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year 1--*-SMB --*4-LMB "*A-Visibility,

Figure 4. 4-4. NAR-5 smallmouth and largemouth bass median densities, and mean visibilities, 1987-2000.

50

-3.5 45 3

,40 P35 2.5

~30-Z S30

-*--2 "E 2 5 -

c"

~v20 1.5>

20-0 015-1 010 5-0.5 5*

0/

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year

["*- SMB LMB -*-Visibility

TABLE 2.0-1 Seasonal summary of North Anna Power Station operation (percent of total Station load) 1978-2000.

Year 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Quarters at 75-100%

Winter 0

43 31 46 78 53 76 87 75 92 75 47 98 63 35 49 96 87 76 98 96 97 84 14 23 31 37 80 26 58 64 96 88 45 99 26 98 89 80 83 91 64 98 80 81 90 91 14 qblnatable2.0-1/xls 52 Spring Summer Fall 42 44 53 67 19 96 16 82 62 23 94 87 69 84 92 79 75 98 83 97 85 87 100 13 Quarterly Average 27.5

29.5 46.5 68.8 42.8 72.8 55.5 81.8 76.3 51.8 91.3 56.3 81.5 82 69.5 73.3 88.5 86.5 80.8 93 89 92 94 45 0

65 82 48 84 66 62 80 47 97 65 61 92 71 82 91 97 66 97 94 93 100 12

TABLE 3.1-1.

SUMMARY

OF NORTH ANNA FIXED RECORDER TEMPERATURE DATA DURING 2000.

VALUES ARE MEANS OF DAILY HIGH, MEAN AND LOW TEMPERATURES (IN DEGREES CELSIUS).

ALL INSTRUMENTS ARE LOCATED AT THE SURFACE EXCEPT FOR NALSTIO WHICH IS AT MID-DEPTH.

"N" INDICATES DATA MISSING DUE TO INSTRUMENT MALFUNCTION OR DAMAGE.

HOURS OF DATA COLLECTED ARE SHOWN.

TATION NO.

6 5

4 2

1 3

10 7

8 9

TYPE NAL719ST NAL719NT NAL2O8T NALINT HIGH 5.6 5.6 6.9 8.0 MEAN 5.4 5.3 6.6 7.8 LOW 5.2 5.1 6.4 7.6 HOURS 743 744 743 744 YEAR=2000 NALTHIST 8.0 7.7 7.6 614 MONTH=JANUARY NALBRPTT 10.2 9.9 9.6 744 NALSTIO NADISCI NAWHTF2 NAWHTF3 NARIV601 11.0 20.7 15.7 12.7 10.2 10.6 20.5 15.1 12.4 9.8 10.2 20.3 14.6 12.2 9.3 743 744 744 743 744 YEAR=2000 MONTH=FEBRUARY TYPE NAL719ST NAL719NT NAL208T NALINT NALTHIST NALBRPTT NALST1O NADISCI NAWHTF2 NAWHTF3 NARIV601 HIGH MEAN LOW HOURS 6.0 5.6 5.3 696 5.9 5.4 5.2 696 5.8 5.4 5.1 696 7.2 6.9 6.6 696 7.7 7.3 7.0 696 9.6 9.1 8.7 696 10.0 9.4 8.8 696 18.5 18.2 17.9 696 15.0 14.4 13.8 696 12.5 12.1 11.8 696 9.9 9.3 8.8 696 TYPE NAL719ST NAL719NT NAL208T NALINT HIGH 12.5 12.5 12.5 12.9 MEAN 11.9 11.8 12.1 12.4 LOW 11.3 11.2 11.7 12.0 HOURS 744 744 744 744 TYPE NAL719ST NAL719NT NAL208T NALINT HIGH 15.9 15.6 15.3 16.1 MEAN 15.2 15.0 14.8 15.6 LOW 14.6 14.5 14.4 15.1 HOURS 719 719 719 719 YEAR=2000 NALTHIST 13.0 12.5 12.1 744 YEAR=2000 NALTHIST 15.5 15.1 14.8 719 YEAR=2000 TYPE NAL719ST NAL719NT NAL208T NALINT NALTHIST HIGH 24.1 24.1 23.5 21.1 23.5 MEAN 23.2 23.3 22.8 20.4 22.8 LOW 22.5 22.5 22.2 19.7 22.1 HOURS 744 744 744 744 744 MONTH=MARCH NALBRPTT 13.8 13.4 13.0 744 MONTH=APRIL NALBRPTT 16.5 16.1 15.7 719 MONTH=MAY NALBRPTT 23.3 22.7 22,1 744 NALST1O NADISCI NAWHTF2 NAWHTF3 NARIV601 13.3 23.7 18.6 16.8 14.1 12.6 23.3 18.0 16.3 13.5 11.8 22.8 17.5 15.9 13.0 744 744 744 744 744 NALST1O NADISC1 NAWHTF2 NAWHTF3 NARIV601 16.0 24.6 20.9 18.8 16.3 15.5 24.0 20.2 18.3 15.7 15.0 23.4 19.7 17.9 15.2 718 719 719 719 718 NALST1O NADISC1 NAWHTF2 NAWHTF3 NARIV601 20.9 30.2 28.0 26.2 23.0 20.2 29.7 27.3 25.6 22.1 19.4 29.4 26.7 25.1 21.3 744 744 744 744 744 ST

TABLE 3.1-1(CONT.).

SUMMARY

OF NORTH ANNA FIXED RECORDER TEMPERATURE DATA DURING 2000.

VALUES ARE MEANS OF DAILY HIGH, MEAN AND LOW TEMPERATURES (IN DEGREES CELSIUS).

ALL INSTRUMENTS ARE LOCATED AT THE SURFACE EXCEPT FOR NALSTIO WHICH IS AT MID-DEPTH.

A "*"

INDICATES DATA MISSING DUE TO INSTRUMENT MALFUNCTION OR DAMAGE.

HOURS OF DATA COLLECTED ARE SHOWN.

STATION NO.

6 5

4 2

1 3

10 7

8 9

YEAR=2000 MONTH=JUNE TYPE NAL719ST NAL719NT NAL208T NALINT NALTHIST NALBRPTT NALSTIO NADISCI NAWHTF2 NAWHTF3 NARIV601 HIGH 27.7 27.5 27.3 25.5 27.3 27.2 25.3 34.5 32.7 30.1 27.0 MEAN 26.9 26.7 26.6 24.9 26.6 26.6 24.6 34.2 32.0 29.5 26.1 LOW 26.3 26.1 26.0 24.2 26.1 26.2 23.9 33.9 31.3 29.1 25.3 HOURS 720 720 720 720 720 720 720 720 720 720 720 YEAR=2000 TYPE NAL719ST NAL719NT NAL208T NALINT NALTHIST HIGH 29.2 29.1 29.2 28.8 29.6 MEAN 28.6 28.4 28.7 28.3 29.1 LOW 28.1 27.9 28.3 27.8 28.6 HOURS 744 744 744 744 744 MONTH=JULY NALBRPTT 29.8 29.3 28.9 744 NALSTIO NADISC1 NAWHTF2 NAWHTF3 NARIV601 28.6 37.0 34.6 32.3 29.7 28.0 36.8 33.9 31.6 28.6 27.5 36.6 33.2 30.7 27.7 744 744 744 744 743 TYPE NAL719ST NAL719NT NAL208T NALINT HIGH 28.1 27.7 28.7 28.5 MEAN 27.6 27.2 28.2 28.0 LOW 27.2 26.8 27.8 27.7 HOURS 744 744 744 744

Y TYPE NAL719ST NAL719NT NAL208T NALINT HIGH 24.9 26.5 27.8 26.3 MEAN 24.4 25.9 27.4 25.9 LOW 24.0 25.5 27.0 25.7 HOURS 720 720 720 720 TYPE NAL719ST NAL719NT NAL208T NALINT HIGH 15.9 20.5 22.1 21.6 MEAN 15.4 20.0 21.7 21.2 LOW 15.0 19.5 21.3 20.9 HOURS 744 744 744 744 YEAR=2000 NALTHIST 28.8 28.3 27.9 744 MONTH=AUGUST NALBRPTT 29.4 28.9 28.6 744 YEAR=2000 MONTH=SEPTEMBER NALTHIST NALBRPTT 27.5 27.8 27.1 27.3 26.8 27.0 720 720 YEAR=2000 MONTH=OCTOBER NALTHIST NALBRPTT 22.2 23.3 21.8 22.9 21.5 22.6 743 744 NALSTIO NADISCI NAWHTF2 NAWHTF3 NARIV601 28.1 35.7 33.0 31.7 29.4 27.6 35.5 32.4 31.3 28.4 27.2 35.3 31.8 30.9 27.6 744 744 744 744 744 NALSTIO NADISC1 NAWHTF2 NAWHTF3 NARIV601 27.8 32.7 32.7 29.5 28.3 27.5 32.5 32.0 29.0 27.3 27.1 32.2 31.3 28.6 26.5 720 720 720 720 720 NALSTIO NADISCI NAWHTF2 NAWHTF3 NARIV601 23.4 28.8 24.6 24.9 22.5 22.9 28.4 24.0 24.5 21.6 22.5 28.1 23.4 24.2 20.9 744 744 744 744 744

TABLE 3.1-1(CONT.).

SUMMARY

OF NORTH ANNA FIXED RECORDER TEMPERATURE DATA DURING 2000.

VALUES ARE MEANS OF DAILY HIGH, MEAN AND LOW TEMPERATURES (IN DEGREES CELSIUS).

ALL INSTRUMENTS ARE LOCATED AT THE SURFACE EXCEPT FOR NALST1O WHICH IS AT MID-DEPTH.

A "*" INDICATES DATA MISSING DUE TO INSTRUMENT MALFUNCTION OR DAMAGE.

HOURS OF DATA COLLECTED ARE SHOWN.

STATION NO.

6 5

4 2

1 3

10 7

8 9

YEAR=2000 MONTH=NOVEMBER-----------------------------------------------------

TYPE NAL719ST NAL719NT NAL208T NALINT NALTHIST NALBRPTT NALSTIO NADISCI NAWHTF2 NAWHTF3 NARIV601 HIGH 10.2 12.9 15.2 15.2 15.7 18.0 18.2 25.8 19.4 19.2 17.5 MEAN 9.9 12.6 14.9 15.0 15.5 17.8 17.9 25.7 19.0 19.0 17.0 LOW 9.6 12.3 14.7 14.8 15.3 17.5 17.6 25.5 18.6 18.7 16.2 HOURS 720 720 720 720 720 720 720 720 720 720 720 TYPE NAL719ST NAL719NT NAL2O8T NALINT HIGH 4.8 5.2 8.2 9.0 MEAN 4.6 5.0 7.9 8.9 LOW 4.4 4.8 7.7 8.7 HOURS 744 744 744 744 YEAR=2000 NALTHIST 8.6 8.4 8.2 744 MONTH=DECEMBER NALBRPTT 13.4 13.1 12.8 744 NALST1O NADISCI NAWHTF2 NAWHTF3 NARIV601 12.2 21.9 14.8 13.9 11.8 12.0 21.7 14.3 13.6 11.4 11.7 21.5 13.9 13.4 10.8 744 744 744 744 744

NORTH ANNA LAKE SURVEY SHOWING TEMPERATURES (IN CELSIUS D nS

] MEASURED AT ONE METER INTERVAL DEPTHS FOR STATIONS IN LAKE ANNA.

I----------------------------------------------STATION-A B

C D

E 9.1 9.1 9.0 8.9 8.9 8.9 8.9 8.9 8.8 8.7 7.5 7.3 7.1 7.0 6.9 6.8 6.8 6.8 6.7 6.7 6.7 6.7 9.1 9.1 9.0 8.8 8.7 8.6 8.5 8.5 8.5 8.4 8.3 7.9 7.8 7.7 7.5 7.5 7.5 8.8 8.6 8.5 8.3 8.0 8.0 7.8 7.7 7.6 7.5 7.4 7.3 7.1 7.1 7.0 7.0 6.8 6.8 6.8 6.8 8.8 8.7 8.6 8.5 8.3 8.0 7.8 7.7 7.6 7.5 7.4 7.3 7.2 7.1 7.0 7.0 6.9 6.8 6.8 6.7 8.9 8.8 8.8 8.6 8.3 7.9 7.7 7.,6 7.6 7.5 7.5 7.3 7.2 7.1 7.1 7.0 6.9 6.8 6.8 8.3 8.2 8.1 8.0 7.0 7.8 7.8 7.7 7.6 7.6 7.4 7.1 6.8 6.6 6.4 6.4 6.4 6.3 6.3 6.2 6.2 G

H I

J K

L M

N 8.1 8.0 7.8 7.7 7.6 7.6 7.6 7.5 7.4 7.3 7.1 6.9 6.7 6.6 6.3 6.1 6.0 5.9 5.9 5.9 7.1 6.9 6.8 6.7 6.5 6.3 6.0 5.9 5.8 5.8 5.7 5.6 5.5 5.3 5.2 5.1 6.7 6.5 6.3 6.2 6.1 6.0 5.9 5.9 5.9 5.8 5.6 5.5 5.3 5.0 5.8 5.7 5.7 5.6 5.5 5.5 5.4 5.4 5.4 5.3 5.1 5.0 4.8 4.7 4.7 4.1 4.0 4.0 4.0 3.9 3.9 3.9 3.9 3.9 3.9 3.9 3.9 3.9 3.9 4.7 4.6 4.4 4.3 4.2 4.1

.4.1 4.0 TABLE 3.1-'

I DEPTH DATE (M) 02/10/2000 0

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21

TABLPE31-2(CONT.).

NORTH ANNA LAKE SURVEY SHOWING TEMPERATURES (INI SIUS DEGREES)

MEASURED AT ONE METER INTERVAL DEPTHS FOR STATIONS IN LAKE ANNA.

STATION-S DEPTH DATE (M)

A B

C 0

E F

G H

I J

K L

H N

06/13/2000 0

27.4 27.3 26.9 29.4 27.1 27.5 27.7 28.0 28.7 28.5 29.2 27.6 28.0 27.9 1

27.1 27.3 26.7 27.1 26.9 27.4 27.5 27.9 28.5 28.3 28.0 27.5 27.9 27.8 2

26.9 27.0 26.6 26.9 26.8 27.3 27.2 27.6 28.4 28.2 27.7 27.3 27.5 27.3 3

26.7 26.5 26.3 26.6 26.7 27.2 26.8 27.3 28.1 26.5 26.4 26.1 26.5 25.5 4

26.5 25.6 25.7 26.2 26.4 27.0 26.1 24.8 25.6 25.5 25.7 24.6 24.6 24.4 5

26.3 24.4 25.3 25.6 26.1 26.6 25.7 24.4 24.6 25.0 24.8 23.8 23.8 23.3 6

25.8 24.1 25.2 25.5 26.0 26.2 25.4 24.1 24.0 24.1 24.1 23.4 22.9 23.1 7

25.3 23.7 24.8 25.0 25.4 25.4 24.6 23.4 23.5 23.6 23.2 23.2 22.4 23.0 8

24.4 23.3 24.5 24.6 24.6 24.5 23.6 23.2 23.1 23.5 22.9 22.3 9

23.6 22.4 24.1 23.6 24.1 23.8 20.4 23.2 22.8 22.8 22.5 10 20.2 19.7 20.9 21.0 21.4 20.9 20.8 20.2 20.4 20.5 20.2 11 19.8 19.3 20.5 20.5 20.7 20.4 20.1 19.9 20.1 19.7 20.0 12 19.6 19.1 20.0 19.9 20.5 19.9 19.7 19.6 19.8 19.4 19.6 13 18.7 19.0 19.7 19.5 20.2 19.5 19.3 19.5 19.6 19.4 19.6 14 18.2 19.0 19.4 19.1 19.4 19.2 19.0 19.5 19.2 19.6 15 17.9 19.0 19.0 18.7 19.1 19.0 18.7 19.6 16 17.6 19.0 18.5 18.2 18.5 18.7 18.5 17 15.8 17.8 17.2 18.4 18.1 18.0 18 15.0 16.9 16.2 18.4 17.3 17.4 19 14.7 16.0 16.2 16.8 16.2 20 14.4 16.8 21 14.4

TABLE'.I-2(CONT.).

NORTH ANNA LAKE SURVEY SHOWING TEMPERATURES (IN!tSIUS DEGREES)

MEASURED AT ONE METER INTERVAL DEPTHS FOR STATIONS IN LAKE ANNA.

STATION-DEPTH DATE (M)

A B

C D

E F

G H

I J

K L

M N

08/22/2000 0

28.4 28.4 28.4 28.2 28.2 28.0 27.9 27.6 27.3 27.1 26.8 26.4 26.5 27.1 1

28.4 28.4 28.4 28.2 28.2 28.0 27.9 27.6 27.3 27.1 26.9 26.5 26.5 26.9 2

28.4 28.5 28.4 28.3 28.2 28.0 27.9 27.6 27.3 27.1 26.9 26.4 26.4 26.6 3

28.4 28.5 28.4 28.3 28.2 28.0 27.9 27.6 27.3 27.1 26.9 26.4 26.2 26.4 4

28.4 28.5 28.2 28.2 28.1 28.0 27.8 27.5 27.2 27.1 26.9 26.3 26.2 26.2 5

28.4 28.5 28.1 28.1 28.0 27.9 27.8 27.4 27.2 27.1 26.8 26.3 26.1 26.1 6

28.4 28.4 27.9 28.0 28.0 27.9 27.8 27.3 27.2 27.1 26.9 26.3 26.1 26.0 7

28.4 28.3 27.9 27.9 27.9 27.9 27.8 27.2 27.2 27.1 26.8 26.3 26.1 26.0 8

28.4 28.1 27.8 27.8 27.9 27.9 27.8 27.1 27.2 27.0 26.8 26.1 9

28.4 28.1 27.8 27.8 27.9 27.8 27.7 27.0 27.1 27.0 26.6 10 28.0 27.9 27.8 27.7 27.9 27.8 27.6 27.0 27.1 27.0 26.5 11 27.9 27.7 27.7 27.7 27.8 27.7 27.5 26.9 27.1 27.0 26.5 12 27.7 27.2 27.6 27.7 27.8 27.5 27.4 26.9 27.1 26.9 26.5 13 27.5 27.1 27.6 27.6 27.6 27.4 27.3 26.8 26.9 26.7 14 27.3 27.0 27.5 27.4 27.3 27.4 27.2 26.8 26.6 15 26.9 27.0 27.3 27.1 27.1 27.3 27.1 26.7 16 26.6 26.9 27.1 26.7 26.8 26.8 26.8 17 25.8 26.1 26.1 26.6 26.7 26.5 18 24.9 25.5 24.9 26.3 26.4 26.2 19 24.4 25.0 24.1 26.2 26.1 20 22.5 26.2 21 19.7

TABL t

.I1-2(CONT.).

NORTH ANNA LAKE SURVEY SHOWING TEMPERATURES (It LSIUS DEGREES)

MEASURED AT ONE METER INTERVAL DEPTHS FOR STATIONS IN LAKE ANNA.

STATION-DEPTH DATE (M) 11/17/2000 0

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 A

B C

D E

17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.7 17.6 17.6 17.5 17.4 17.4 17.4 17.4 17.4 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.1 18.0 18.0 17.6 17.6 17.6 17.6 17.6 17.6 17.6 17.5 17.5 17.4 17.3 17.1 17.1 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.6 17.6 17.6 17.6 17.6 17.6 17.6 17.4 17.3 17.2 17.2 17.1 17.1 17.0 17.0 17.0 16.9 16.9 16.9 16.9 17.5 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.4 16.7 17.2 16.6 17.1 16.6 17.1 16.6 17.1 16.6 17.0 16.5 17.0 16.5 17.0 16.4 16.9 16.4 16.9 16.4 16.9 16.4 16.4 16.4 G

H I

J K

L 1

N 16.3 16.1 15.8 15.7 14.8 14.1 13.1 13.1 16.3 16.1 15.8 15.7 14.8 14.1 13.1 13.1 16.3 16.1 15.8 15.7 14.8 14.0 13.1 13.0 16.3 16.1 15.8 15.7 14.8 14.0 13.0 12.9 16.3 16.1 15.8 15.7 14.8 13.9 12.9 12.8 16.3 16.1 15.8 15.7 14.8 13.9 12.9 12.7 16.3 16.1 15.8 15.6 14.8 13.8 12.8 12.7 16.3 16.0 15.8 15.6 14.8 13.8 12.8 12.6 16.2 15.9 15.8 15.6 14.8 16.2 15.9 15.7 15.6 14.7 16.2 15.9 15.7 15.6 14.7 16.2 15.9 15.7 15.5 14.6 16.2 15.8 15.7 15.4 14.6 16.1 15.8 15.7 15.2 14.6 16.1 15.8 15.2 14.5 16.1 15.8 14.5 16.0 16.0 15.9 15.9

TABLE I'-1 Surface water temperature (C), conductivity (umhos),pH (standar$'*lts) and dissolved oxygen (mg/I) recorded at time of sampling during 2000 FEBRUARY MAY Electrofish Stations Dike 1 WHTF Dike 3 WHTF Lagoon 1 Lagoon 3 North Anna Arm Thurman Island Dike 1 Lake Dike 3 Lake Lower Lake Cove Gillneting Stations Lagoon 1 Lagoon 3 North Anna Arm Thurman Island Levy Creek Lower Lake AUGUST Electrofish Stations Dike 1 WHTF Dike 3 WHTF Lagoon 1 Lagoon 3 North Anna Arm Thurman Island Dike 1 Lake Dike 3 Lake Lower Lake Cove Temperature Conductivity 18 52 13 51 17 52 13 51 8

64 9

50 9

50 11 51 11 51 19 14 8

9 11 12 51 51 65 50 51 51 pH 6

6 6

8 7

7 7

7 6

6 7

7 7

Dissolved Oxygen 9

8 9

8 13 10 10 9

9 9

9 13 11 10 9

Electrofish Stations Temperature Dike 1 WHTF 27 Dike 3 WHTF 29 Lagoon 1 28 Lagoon 3 28 North Anna Arm 26 Thurman Island 26 Dike 1 Lake 22 Dike 3 Lake 22 Lower Lake Cove 23 Gillneting Stations Lagoon 1 27 Lagoon 3 27 North Anna Arm 26 Thurman Island 24 Levy Creek 23 Lower Lake 22 Conductivity 46 47 47 47 49 45 45 45 45 47 46 51 45 46 46 pH 7

7 7

7 8

8 7

7 7

7 7 8

8 7

7

)issolved Oxygen 9

8 8

9 11 8

8 8

9 8 8 11 9

9 8

OCTOBER Temperature Conductivity 36 47 32 46 36 46 32 45 31 66 31 60 30 61 30 61 32 61 Gillneting Stations Lagoon 1 36 Lagoon 3 32 North Anna Arm 31 Thurman Island 32 Levy Creek 31 Lower Lake 31 61 7

61 8

67 8

61 8

61 7

61 8

pH

)issolved Oxygen 7

7 7

7 8

8 8

7 8

9 8

8 6

7 9

8 7

7 Electrofish Stations Temperature Dike 1 WHTF 26 Dike 3 WHTF 20 Lagoon 1 25 Lagoon 3 20 North Anna Arm 13 Thurman Island 16 Dike 1 Lake 16 Dike 3 Lake 18 Lower Lake Cove 17 Gillneting Stations Lagoon 1 27 Lagoon 3 21 North Anna Arm 13 Thurman Island 16 Levy Creek 18 Lower Lake 19 Conductivity 48 51 48 49 50 45 43 44 44 47 47 46 45 44 44 pH 7

7 7

)issolved Oxygen 9

9 9

9 11 9

9 8

9 9

9 11 10 9

9

Table 3.2-2. Fishes collected in Lake Anna and the WHTF by gill netting in 2000 FAMILY Clupeidae Cyprinidae Catostomidae Ictaluridae Moronidae Centrarchidae Percidae SPECIES Dorosoma cepedianum Dorosoma petenense Cyprinella analostana Cyprinus carpio Erimyzon oblongus Ameiurus catus Amaiurus natalis Ictalurus punctatus Morone americana Morone saxatilis Lepomis auritus Lepomis macrochirus Lepomis microlophus Micropterus: salmoides Pomoxis nigromaculatus Stizostedion vitreum LAKE x

x x

x WHTF x

x x

x NAOlX35q 61

TABLE 3.2-3 NUMBER AND WEIGHT (g) OF FISHES BY STATION COLLECTED BY GILL NETTING AT LAKE ANNA DURING 2000 STATION FEBRUARY MAY AUGUST OCTOBER TOTAL CPUE LAGOON I 15666 19

32

28

106 8857

10320

17906

52749 15

5560

K NUMBER

36 WEIGHT

36614 NUMBER

WEIGHT

NORTH ANNA ARM

NUMBER WEIGHT

THURMAN ISLAND NUMBER

WEIGHT

TOTALS NUMBER

WEIGHT

28 17353 98 17555 14

16123

218

108871

24

20

10

69 10058

5730

3845

25193 16

28

11

91 5614

5372

2781

50381 6*

20*

2049

6567

26.5 13187.25 17.25 6298.25 22.75 12595.25 16

70

17.5 7013

32982

8245.5 78

296

24697

82230

74 20557.5 17

78

6278

44472

160

62520

710

288007

19.5 11118 29.6 12000.3 74 *

- 46

22411

17567

29

17006

168

65995

18

5065

164

50621

62 27 NUMBER WEIGHT NUMBER

WEIGHT

LAGOON 3 LEVY CREEt LOWER LA

w I ABLE 3.2.4 GILL NET

SUMMARY

2000 (ILL NET - LAKE ITATION:ALL STATIONS FE SPECIES Nu D.....

1 Ill, OJJIlIO( IlI iPi diijiI.3luitaCla I. punLjCtLtiS A. citus S ViLi'tLI1ll

-1. sahlloide1 U

pu)le 1 lll Is 5 C. Mrpio L. maciau~hiitis L 3MIilLUS E.ailonljful A. n1Jltli roul No.

10o.11 Wi.

GILL NET TOTALS - WHTF STATION-ALL STATIONS F

SPECIES N

U 'iplllljllull t

I 1MIiLIaJUi M Nil i.OiS~

(.,311l.3 A. Ia iluo L.

uinoolophus M Saxalisi S VILIC11l11 loul No.

Totil WE.

BRUARY UMBER 3ý 4

3 2

WEIGHT 9

3372 4

49705 7

5901 I

5935 0

7011 I

3008 6

5530 5

3866 1

2990 I

250 MAY NUMBER 52 13 19 to 10 14 78 176 87645 FEBRUARY NUMBER WEIGHT 12 4508 18 5580 5

2082 2

314 2

859 2

7569 WEIGHT 13416 9184 1967 790 9094 3957 1914 6727 24 AUGUST NUMBER WEIGHT S......................................

68 12786 8

653 3

240 14 9933 2

182 1

1324 5

1220 5

41 4

8135 OCTOBER NUMBER WEIGHT 36 8329 16 16225 B

1178 32 1877 12 4246 3

850 6

4656 4

29 2

2570 2

542 I

S4 III 125 47082 MAY=

==

=

MAY NUMBER 19 6

S 8

WEIGHT 7455 1197 286 220 193 4913 4127 323 201 266 112 34572

-:=

=

=*

AUGUST NUMBER WEIGHT 21 7143 3

973 17 5163 SI 60 6

2114 4

595 NO NU 122 40769

)VEMBER UMBER WEIGHT 7

3004 8

1529 I

272 10 853 3

1376 4

12000 I

7 4

2711 I

314

S....................

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

41 43 52 38 21226 18914 16049 21751 TOTALS

% Of TOTAl NUMBER WEIGHT NUMBER WEIGHT 195 37903 36 I8 73 75114 14 36 72 9698 13 5

66 8842 12 4

46 30284 9

14 30 7996 6

4 13 11510 2

5 13 7000 2

3 9

69 2

0 9

20421 2

10 3

792 I

0 2

29 0

0 1

54 0

0 I

78 0

0 I

1 0

0 I

266 0

0 535 100 210068 100 TOTALS

% OF TOTAL NUMBER WEIGHT NUMBER WEIGHTi 59 22110 34 28 35 9280 20 12 24 7804 14 10 lB 1446 10 2

12 4542 7

6 8

4913 5

6 7

23696 4

30 6

925 3

5 2912

3 4

I 314 *1 I

0 175 100 77940 100 i

Table 3.3-1. Fishes collected in Lake Anna and the WHTF by electrofishing in 2000 LAKE x

x x

WHTF x

x x

FAMILY Clupaidae Cyprinidae Catostomidae Ictaluridae Poeciliidae Moronidae Centrarchidae Percidae SPECIES Dorosoma cepedianum Cyprinella analostana Cyprinus carpio Notropis hudsonius Notropis procne Erimyzon oblongus Ameiurus catus Amaiurus natalis Amaiurus nebulosus Ictalurus Punctatus Gambusia affinis Morone americana Lepomis auritus Lepomis cyanellus Lepomis gibbosus Lepomis gulosus Lepomis macrochirus Lepomis microlophus Micropterus salmoides Pomoxis nigromaculatus Perca flavescens NA01X356 64

TABLE 3.3-2 NUMBER AND WEIGHT (g) OF FISHES BY STATION COLLECTED BY ELECTROFISHING AT LAKE ANNA DURING 2000 STATION

FEBRUARY

MAY AUGUST

OCTOBER TOTAL LAGOON I NUMBER

71

41

42

127

281

WEIGHT

554

2362

675

2447

6038

LAGOON 3 NUMBER

WEIGHT

DIKE 1-WHTF NUMBER WEIGHT DIKE 3-WHTF NUMBER WEIGHT DIKE I-LAKE NUMBER WEIGHT DIKE 3-LAKE NUMBER WEIGHT LOWER LAKE NUMBER WEIGHT

THURMAN ISLANE NUMBER WEIGHT NORTH ANNA ARI NUMBER WEIGHT TOTAL NUMBER TOTAL WEIGHT 59

232

594*

5810*

363*

4772*

216*

3195*

133*

1143*

64

782

70

13718

61

965

130

1756

61

581

122

2461 154

1589

64

1767

32

1533

46

1395

107

315

98

693*

1269

5042

74

770

80

2003

35

478

14*

306

183

3877

421 4551 361

2846

166

919

273

2907

1515

13877

681

10000

839

12210

683

6056

308

3774

19

301

422

299

4610

20160

40*

103

59

22*

1450

14333

9344

5253 1610

768

467

2381

31656

27347

16539

29860

224

30380

5226

105402

CPUE 70.25 1509.5 68.25 726.75 378.75 3469.25 170.25 2500 209.75 3052.5 170.75 1514 77 943.5 105.5 5040 56 7595 145.2 2927.8

r TABLE 3.3-3 ELECTROFISH

SUMMARY

2000 ELLLTROFISH - LAKE

',TATION.ALL STATIONS FEBRUARY SPECIES NUMBER WEIGHT(S)

Lm tIa I ochlius NtIudIOilul L.

auf icul I')

uinmokles L.gulomiu L..niciolophu$

D.ItpcdiiinullI L Lynllellul P.I' u*

I oIaculatus N p0-.olelie i-i Jtun:

jiuJI C ý.1 (1 pio

( ci.v tl ll A itbukiust

(,.hulbooki L ibbosus E obloulgus A catus Tol I No.

loitl Wi.(i)

ELECTROFISH TOTALS - WHTF STATION:ALL STATIONS SPECIES L.tinc I dlil us C

tL yaiellus

1-1 saJlmloiatsl ilotoilhus I lit iL U

( ji.l~alustalla.

L.gulolus I Il~lltat~lUs N pi*cnIe A.t atus A

bli*ioUS c.calpio L (11310li A nlalis Total No.

Total Wi.(R) 396 33 58 13 a

4078 2726 11683 179 390 5

45 6

13 MAY NUMBER 364 33 I5 16 II 3

II WEIGHT(g) 4059 540 2977 269 791 466 161 1210 3

6 217 3

10715 AUGUST NUMBER WEIGHT(g) 119 1846 28 473 15 2420 II 283 5

89 19 2976 I

21 5

289 2

4000 2

32 OCTOBER NUMBER WEIGHT(g) 987 7126 156 922 47 1008 20 3989 15 201 10 235 7

957 13 105 7

97 6

7 I

3500 2

30 5'

TOTALS NUMBER 1866 156 141 B08 55 34 29 27 23 7

6 6

6 4

3 2

WEIGHT(g) 17110 922 4748 21070 932 1505 4399 332 1596 Is 7

217 18215 63 262 5

I 13 I

3 SI 100 I

I100 I

69 I

69 523 475 207 1271 2476 20288 21683 12430 18177 72579

== =2===== = -

==f I

=

-=

==--

=-==

=

==

FEBRUARY MAY AUGUST OCTOBER TOTALS NUMBER WEIGHT(gi NUMBER WEIGHT(g)

NUMBER WEIGHT(g)

NUMBER WEIGHT(s) 1012 9286 241 2120 174 1124 1051 7971 2478 20501 19 163 8

125 49 1125 Is 127 91 1539 20 1087 10 664 15 121 9

1010 54 2882 13 532 13 1387 3

40 13 180 42 2140 6

102 4

36 4

7 9

512 23 657 3

4 6

13 9

9' B

26 3

58 7

204 3

66 4

37 17 365 3

126

'4 1115 1

41511 7

S9 1674 S8 1

a II 6

1802 6

1802 2

24 1087 11368 293 5664 I

1200 I

2 260 4109 1110 11681 2

24 I

1200 I

2 2750 32823

% OF TOTAL NUMBER WEIGIIT 75 24 6

I 6

7 4

29 2

I I

2 I

6 I

0 2

0 0

0 25 0

0 0

2 0

0 100 100

% OF TOTAL NUMBER WEIGHT 90 62 3

2 2

0 s

9 7

2 0

S 0

0 0

5 0

0 0 4 0

100 100

TABLE 3.4-1 ESTIMATE OF HYDRILLA (Hydrilla verticillata) COLONIZATION OF LAKE ANNA and WHTF North Anna Power Station 2000 LAKE ANNA TOTAL ACRES AVAILABLE ACRES OF HABITAT( I)

ACRES OF HYDRILLA COLONIZATION PERCENT OF AVAILABLE HABITAT COLONIZED WASTE HEAT TREATMENT FACILITY LAGOON I LAGOON 2 9600 I1 225 3885 65 2%

110 3

3%

2206 1158 16 2%

LAGOON 3 969 442 10 2%

(1) ACRES OF 15 FEET OR LESS WATER DEPTH WHTF TOTAL 3400 1710 29 2%

Table 4.1-1 Mean, maximum, and minimum hourly water temperatures (C) recorded in the North Anna River, at station NAR-1 by month, during 2000. Sample size (n) equals the number of hourly observations recorded each month.

NAR-1 Month Mean Max Min n

January 9.8 13.5 5.4 744 February 9.3 13.1 6.5 696 March 13.5 15.9 12.0 744 April 15.7 18.4 13.4 718 May 22.1 25.4 17.3 744 June 26.1 30.1 22.2 720 July 28.6 31.2 25.7 743 August 28.4 31.2 26.4 744 September 27.3 30.8 23.2 720 October 21.6 28.6 18.7 744 November 17.0 20.4 9.1 720 December 11.4 14.5 7.7 744 68

Table 4.3-1.

Number and biomass (g) of fishes collected during May, August and September, 2000 electrofishing surveys of the North Anna River.

NAR-1 Family

_ _ Species-Petromyzontidae Petromyzon marinus Anguillidae Anguilla rostrata Cyprinidae Cyprinella analostana Lythrurus ardens Nocomis leptocephalus Nocomis micropogon Notropis amoenus Notropis procne Notropis rubellus Semotilus corporalis Catostomidae Erimyzon oblongus Hypentelium nigricans Ictaluridae Ameiurus natalis Ameiurus nebulosus Noturus gyrinus Noturus insignis Centrafchidae Lepomis auritus Lepomis macrochirus Micropterus dolomieu Micropterus salmoides Percidae Etheostoma olmstedi Etheostoma vitreum Percina peltata Total NAR-2 Number Tota/_Weight -_-

Number Tota/lWeight_

NAR-4 NAR-6 Total

_.Number Total WVejqht Number Totsl Weiht _

Number Totsa Weig!ht 5

55 1304.1 4

9.6 16 41.7 6

26.0 8

111.9 4

1656.0 36 167.5 98 6

1 1

1642.4 129.7 6.8 512.8 2

5.1 15 54.8 252 4167.4 14 432.5 2

17.8 1

1.3 1

1.4 6

60.3 3

207.9 4

9.5 9

16.5 41 2

2 4

3 1

11 282.9 14.9 288.0 61.3 3.8 1.7 17.8 104 1417.6 94.5 12 281.5 7

84 3

7 22.7 135.1 24.0 118.9 1

1.6 14 76.8 4

18 6

8.6 1

3.0 3

68.1 1

4.8 2

2.9 6

3.3 3

49.3 16.2 1

17.3 29.4 66 582.4 5

7.3 1

3.8 204 1130.0 135.6 2

2.7 4

17.1 8

75.0 51 17 1

6 89 2112.6 17 107 4

10 7

2 7

31 68.1 186.7 27.0 187.0 30.8 2.9 6.3 298.3 1

16.2 9

498.5 6

1 4

59 256 25 4

5 13 2

28 409.1 191.7 12.0 3.6 1.3 2.9 3 1 I

128 1295.5 12.2 17.3 17.1 288.4 2916.8 336.3 306.8 674.1 19.8 3.0 79.3 688 8010.6 Number of species North Anna/sjh/xls 13 15 13 20 23

TABLE 4.3-2.

RAW CATCHES OF FISH BY GEAR TYPE IN THE NORTH ANNA RIVER FOR THE PERIOD 1990 2000.

ELECTRIC BACKPACK MAY JULY SEPTEMBER SEINE MAY JULY SEPTEMBER STATIONS BACKPACK ELECTRIC ELECTRIC ELECTRIC STATIONS YEAR BACKPACK BACKPACK BACKPACK SAMPLED TOTAL SEINE SEINE SEINE SAMPLED 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 111 77 153 34 63 114 153 319 127 104 148 82 60 88 152 111 144 215 111 134 120 102 78 145 116 109 131 234 242 209 12 12 12 11 12 4

6 12 12 12 12 349 345 337 172 296 116 261 356 531 776 658 1150 1179 222 271 617 558 598 111 577 1285 422 250 276 408 184 171 283 130 804 715 570 257 228 291 140 510 368 601 12 12 12 12 12 4

6 12 12 12 8

INDICATES THAT NO SAMPLE WAS TAKEN ELECTRIC SEINE TOTAL 2039 3150 2171 729 775 291 548 1311 1097 1482 241 ANNUAL TOTAL 2388 3495 2508 901 1071 407 809 1667 1628 2258 688

Table 4.3-3 Fishes collected from the North Anna River during annual electrofishing surveys, 1981-2000.

Fnmmly SpPr. 6 Ps Petromyzontidae X

X X

X Anguillidae Clupeidae Esocidae Cyprinidae X

X X

X Catostomidae X

X X

X Lampetra appendix Petromyzon marinus Anguilla rostrata Alosa aestivalis Dorosoma cepedianum Esox americanus Esox niger Cyprinella analostana Hyboganthus regius Luxilus comutus Lythrurus ardens Nocomis leptocephalus Nocomis micropogon Notemigonuxc crysoleucas Notropis amoenus Notropis hudsonius Notropis procne Notropis rubellus Phoxinus oreas Rhinichthys atratulus Semotilus corporalis Catostomus commersoni Erimyzon oblongus Hypentelium nigricans Moxostoma macrolepidotum Ameriurus natalis Ameriurus nebulosus Ictalurus punctatus Noturus gyrinus Noturus insignis Aphredoderus sayanus X

X X

Ictaluridae X

X X

X Aphredoderidae Percichthyidae Centrarchidae X

X Morone americana X

X X

X Acantharchurpomotis Centrarchus macropterus Enneacanthus gloriosus Lepomis auritus Lepomis gibbosus Lepomis gulosus Lepomis macrochirus Lepomis microlophus Micropterus dolomieu Micropterus salmoides Pomoxis nigromaculatus Etheostoma olmstedi Etheostoma vitreum Perca flavescens Percina notograma Percina peltata Trinectes maculatus X

X X

X Percidae Soleidae na/xi/042298 X

X X

X.

X 71

-ALLE-j-

-- NAa--J-

-- hLAE- -- NAE-Table 4.3-4.

Ranked abundance of species comprising greater than 80 percent of the pooled annual North Anna River electrofishing catch from all stations, 1981-2000.

A species rank of 1 indicates It was the most abundant fish collected.

Notropis procne Cyprinella analostana Lepomis auritus Notropis rubellus Noturus insignis Percina peltata Anguilla rostrata Lythrurus ardens Nocomis micropogon

-4 Nocomis leptocephalus t-j Sernotilus corporafis Notropis amoenus Hypentelium nlgricans Notemigonus crysoleucas Pomoxis nigromaculatus Lepomis macrochirus Total number of species collected Number of species accounting for >80%

Percent of electrofishing catch 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2

1 1

4 2

3 1

2 7

3 2

2 4

I

?

2 2

5 2

3 2

1 1

3 6

6 1

1 4

2 3

8 4

2 3

8 10 7

4 4

4 6

6 7

6 5

9 7

4 2

3 3

4 6

6 2

4 1

3 7

6 4

2 3

5 5

6 5

5 bi 6

7 7

7 4

4 3

5 4

8 5

6 7

7 8

8 5

8 4

2 10 8

7 8

4 6

4 9

9 9

6 5

a 7

8 6

7 26 27 29 31 31 8

6 7

10 29 32 30 18 25 25 29 25 25 22 7

6 7

7 7

20 24 28 28 23 10 8

7 83 82 81 83 83 83 80 82 80 80 84 83 83 85 82 82 84 80 82 83

"-- indicates species was not among those comprising greater than 80% of the electrofishing catch 4:

Table 4.3-5 Station total numbers and weights for 1998-2000 in the North Anna River 1998 weight 7138.6 3646.0 3448.0 2287.0 1999 weiaht 624 693 609 332 7741.0 2476.0 3146.0 2212.0 2000 weight 252 104 204 128 4167.0 1418.0 1130.0 1295.5 NAR2000/sjh/xI Station NAR-1 NAR-2 NAR-4 NAR-6 373 635 338 283 73

Table 4.4-1.

Number of smallmouth bass and largemouth bass observed during North Anna River snorkel surveys conducted in 2000. Sample size (n) equals the number of times each count was performed in 2000.

Station NAR-1 Smallmouth bass 1 Bank Count n

SMBYOY SMB<11 SMB>11 North South NAR-2 North 1

2 3

1 2

3 1

2 3

South 1

2 3

NAR-4 North 1

2 3

South 1

2 3

NAR-5 North 1

2 3

South 1

2 3

5 4

4 5

4 4

5 5

2 1

9 6

4 7

4 4

0 2

6 7

7 7

6 3

4 2

4 3

5 0

0 0

1 0

1 2

3 2

2 2

1 3

6 5

2 17 10 8

2 1

3 Largemouth bass 2 LMBYOY LMB<12 LMB>12 2

0 0

0 2

2 0

0 0

20 24 24 8

5 7

3 5

2 2

8 3

6 6

3 1

2 0

3 1

0 1

3 1 7

5 7

0 0

1 2

0 1

0 3

3 1

5 3

4 4

4 2

3 6

3 5

4 6

1 2

4 2

3 10 4

1 1

3 4

6 14 6

3 1

2 2

0 1

4 0

0 2

2 3

1 6

0 0

1 1SMYOY were less than or equal to 120 mm, to 280 mm TL.

SMB<1 1 were 121-279 mm, SMB>1 1 were larger than or equal 2 LMBYOY were less than or equal to 120 mm, LMB<1 1 were 121-304 mm, LMB>1 1 were larger than or equal to 305 mm TL.

"74

Table 4.4-2. Cover use by smallmouth bass and largemouth bass in the North Anna River observed during the first of three counts made during snorkel surveys conducted in 2000.

Cover Type NAR-1 Ledge Boulder Wood Vegetation Open*

SMBYOY**

SMB<11 SMB>11 LMBYOY LMB<12 LMB>12 NAR-2 SMBYOY SMB<l11 SMB>11 LMBYOY LMB<12 0

0 0

0 2

0 0

1 3

0 0

2 3

Ledge Boulder Wood 0

0 0

0 1

1 5

0 2

27 6

5 Vegetation 6

0 0

3 4

2 0

0 0

0 1

Open 0

3 0

3 Cover Type NAR-4 Ledge Boulder Wood Vegetation Open SMBYOY SMBI 1 LMBYOY LMB<12 LMB>12 0

0 0

0 6

7 3

0 0

3 1

1 6

1 2

NAR-5 Ledge Boulder Wood Vegetation Open SMBYOY SMB11 LMBYOY LMB<12 0

0 0

2 10 1

1 1

1 2

6 0

1 3

7 1

1 1

LMB>12 0

0 1

1 3

Fish observed in open water were farther than 0.5 m from any cover type.
See Table 4.3-1 for size category definitions.
LMB>12 0
0 4
0 0
North Anna/xl/12/07/98 0
0 0
0 0
0 1
1 0
1 0
Table 4.4-3.
All Stations SMBYOY SMB<11 SMB>11 LMBYOY LMB<12 LMB>12 nalxlI04106/98 Cover use by smallmouth bass and largemouth bass in the North Anna River observed during the first of three counts made during snorkel surveys conducted in 2000. Data for observations at all stations are pooled.
Cover Type Ledge Boulder 0
0 1
0 0
0 1
2 2
0 1
0 Wood Vegetation 2
3 3
0 5
6 10 Open 0
1 0
15 5
0 2
4 3
7 6
"76
5.0 Literature Cited Barko, J. W., D. G. Hardin, and M. S. Matthews. 1982. Growth and morphology of submerged freshwater macrophytes in relation to light and temperature. Canadian Journal of Botany, 60.6: 877-887. 1982.
Bettoli, P. W., M. J. Maceinia, R. L. Noble, R. K. Betsill. 1992.- Piscivory in largemouth bass as a function of aquatic vegetation abundance.
North American Journal of Fisheries Management. 12: 509-516, 1992.
Colle, D. E., and J. V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fisheries Society.
109: 521-531.
Hollander, M., and D.A. Wolfe. 1973. Non-parametric Statistical Methods. John Wiley and Sons, Inc., New York, New York.
Groshens, T.P., and D.J. Orth. 1995. Assessment of the transferability of habitat suitability criteria for smallmouth bass, Micropterus dolomieu. Environmental Biology of Fishes in press.
Jager, H.I., D.L. DeAngelis, M.J. Sale, W. Van Winkle, D.D. Schmoyer, M.J. Sabo, D.J. Orth, and J.A. Lukas. 1993. An individual-based model for smallmouth bass reproduction and young-77
of-year dynamics in streams. Rivers: Studies in the Science, Environmental Policy and Law of Instream Flow 4:91-113.
King, M.A., R.J. Graham, and W.S. Woolcott. 1991. Comparison of growth of smallmouth bass from two tributaries of the York River, Virginia. Pages 6-13 in D.C. Jackson, editor. The First International Smallmouth Bass Symposium.
Mississippi State University Press, Mississippi State, Mississippi.
Lukas, J.A. 1993. Factors affecting reproductive success of smallmouth bass and redbreast sunfish in the North Anna River, Virginia. Master of Science thesis. Virginia Tech, Blacksburg, Virginia.
Lukas, J.A., and D.J. Orth. 1993. Reproductive ecology of redbreast sunfish Lepomis auritus in a Virginia stream. Journal of Freshwater Ecology 8:235-244.
Matthews, W.J. 1982. Small fish community structure in Ozark streams: structural assemblage patterns or random abundance of species? American Midland Naturalist 107(1):42-54.
Sabo, M.J. 1993. Microhabitat use and its effect on growth of age-0 smallmouth bass in the North Anna River, Virginia. Doctoral dissertation. Virginia Tech, Blacksburg, Virginia.
Sabo, M.J., and D.J. Orth. 1995a. Temporal variation in microhabitat use by age-0 smallmouth bass in the North Anna River. Transactions of the American Fisheries Society. In press.
78
Sabo, M.J., and D.J. Orth. 1995b. Effects of early growth rate on growth and survival of age-o smallmouth bass (Micropterus dolomieu Lacepede). Ecology of Freshwater Fish. In press.
Sabo, M.J., and D.J. Orth. 1995c. Net rate of energy gain by age-0 smallmouth bass foraging in different microhabitats within the North Anna River, Virginia. Environmental Biology of Fishes. In press.
Virginia Power. 1986. Section 316(a) demonstration for North Anna Power Station. Virginia Power, Richmond, Virginia.
Virginia Power. 1990. Environmental study of Lake Anna and the lower North Anna River. Annual report for calendar year 1989. Virginia Power, Richmond, Virginia.
Virginia Power. 1992. Environmental study of Lake Anna and the lower North Anna River. Annual report for calendar year 1991, including summary of 1989-1991, Lake Anna and the lower North Anna River. Virginia Power, Richmond, Virginia.
Virginia Power. 1993. Annual report for 1992: Lake Anna and the lower North Anna River.
Annual report for calendar year 1992. Virginia Power, Richmond, Virginia.
Virginia Power. 1995. Annual report for 1994: Lake Anna and the lower North Anna River.
Annual report for calendar year 1994. Virginia Power, Richmond, Virginia.
Virginia Power. 1996. Annual report for 1995: Lake Anna and the lower North Anna River.
Annual report for calendar year 1995. Virginia Power, Richmond, Virginia.
79
Wrenn, W. B., D. R. Lowery, M. J. Maceina, and W. C. Reeves. 1995. Relationships between largemouth bass and aquatic plants in Guntersville Reservoir Alabama. Third National Reservoir Symposium, Chattanooga, Tennessee. 1995.
80

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