ML20038A769

Aquatic Impacts from Operation of Three Midwestern Nuclear Power Stations

ML20038A769
Person / Time
Site:	Cooper, Duane Arnold, Fort Calhoun
Issue date:	10/31/1981
From:	Berkowitz S, Brice J, Elshamy F ENVIRONMENTAL SCIENCE & ENGINEERING, INC.
To:	Office of Nuclear Reactor Regulation
References
CON-FIN-B-6854 NUREG-CR-2337, NUREG-CR-2337-V04, NUREG-CR-2337-V4, NUDOCS 8111160424
Download: ML20038A769 (88)

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NUREG/CR-2337 i

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Aquatic Impacts from Operation of Three Midwestern Nuclear Power Stations Comparative Summary and Recommendations for Nuclear Station Siting and Design Prepared by F. El-Shamy, S. Berkowitz, J. Brice

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Environmental Science and Engineering, Inc.

Prepared for U.S. Nuclear Regulatory Commission DR DOCK O b0b5 P PDR

I NOTICE This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's -

use, or the results of such use, of any information, apparatus product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.

Available from GPO Sales Program i Division of Technical Information and Document Control U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Printed copy price: $4.50 and National Technical Information Service Springfield, Virginia 22161

NUREG/CR-2337 Vol. 4 Aquatic Impacts from Operation of Three Midwestern Nuclear Power Stations

- Comparative Summary and Recommendations for Nuclear Station Siting and Design Minuscript Completed: August 1981 D:ta Published: october 1981 Prepared by F. El-Shamy, S. Berkowitz, J. Brice Environmental Science and Engineering, Inc.

P. o. Box ESE Gainesville, FL 32601 Prepared for Division of Engineering Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission W:.shington, D.C. 20555 NRC FIN B6854

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' ABSTRACT Ecological impacts of 'three midwestern nuclear stations on riverine ecosystems were assessed.- Station location, intake and discharge location and design were evaluated as to their ' interaction with dif ferent t ro ph ic .

~1evels. Fort Calhoun and Cooper Stations, located in Nebraska, utilize once-through cooling systems ;' these stations' cooling waters are withdrawn

' f rom .and returned to the' Missouri River. Duane Arnold Energy Center, located 'in Iowa, has a forced-draf t cooling tower and the station withdraws make-up : water from . the - Cedar River.

Based' on ' the assessment of three particular stations, it was. concluded that '

cooling towers are more environmentally sound 'than once-through cooling systems ' utilizing large volumes of cooling water. Recommend at ions . were made that ef forts used for assessing impacts on lower trophic levels of current and future stations, be- reduced or eliminated based on a case-by-case evaluation. Conversely, the current design and execution-of f tsh. and ichthyoplankton programs deserve a closer look. These trophic' levels call ~ for the expenditure of more ef fort during baseline and

-operational phase monitoring programs, iLt

CONTENTS PAGE

' ABSTRACT iii

1. ' INTRODUCTION l' II. . STATION. DESCRIPTIONS, IMPACTS. AND SUMMARIES OF FINDINGS 3 A. FORT CALHOUN NUCLEAR STATION- 3

1. Station Description 3

2. Characteristtes of the Mtssouri River near Fort Calhoun Station ~ 3

3. .Preoperational' Projections of Station impacts 5

4. Observed and Measured Impacts .

7

'5.

Smumary of Major. Findings at For t Calhoun Station 12 B. ' COOPER NUCLEAR STATION 13

1. Station Descriptton '13

2. Characteristics of the Missouri River near Cooper Nuclear Station 14

3. Preoperational Projections of Station Impacts 16

4. Observed and Measured Impacts 17-

5. Sunmary of Major Findings at Cooper Nuclear Station 19 C. DUANE' ARNOLD ENERGY CENTER 21-

1. Station Description 21

2. Characteristics of the Cedar River near Duane Arnold Energy Center 22

3. Preoperational Projections of Station Impacts 24

4. . Observed and Measured Impacts 31

5. Summary of Major Findings at Duane Arnold Energy Center 33 III. SITING AND DESIGN 35

.A. FORT CALHOUN STATION 35

-1. Siting 35

2. Design 37

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B. COOPER NUCLEAR STATION' 40

_l. Siting ~ 40 -

2. _ Design. 42 y

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P CONTENTS PACE C. DUANE ARNOLD ENERGY CENTER 43

1. Siting 43

2. Design 46 IV. SAMPLING METHODOLOGY: REVIEW AND CRITIQUE 49 A. FORT CALHOUN STATION 49

1. Phytoplankton <49

2. Periphyton 49

3. Zooplankton 50

4. Benthic Macroinvertebrates 50

5. Fish 51

6. Entrainment of Fish Eggs and Larvae 54

7. Impingement of Juvenile and Adult Fish 55

8. Factors Affecting Data Analyses 56 i B. COOPER NUCLEAR STATION 58

1. Phytoplankton 58

2. Periphyton 58

3. Zooplankton 58

'4. Benthic Macroinvertebrates 59

5. Fish 59

! 6. Entrainment of Fish Larvae -60

7. Impingement of Fish 60

8. ' Factors Affecting Data Analyses 60 C. DUANE ARNOLD ENERGY CENTER 62

1. Phytoplankton 62 l 2. Periphyton 63

3. Zooplankton 63

4. Benthic Macroinvertebrates 64

5. Fish 64

6. Entrainment of Fish Eggs and Larvae 65

7. Impingement of Fish' 66

8. Fish Cage Studies 66

9. Factors Affecting Data Analyses 67 V. OVERVIEW 69 A. DISCHARGE TEMPERATURE AND /kT 69 B. INTAKE VOLUME AND INTAKE VELOCITY 71 C. INTAKE SCREEN MESH SIZE' 72 D. INTAKE AND DISCHARGE DESIGN 72 vi

CONTENTS-PAGE E. BIOFOULING CONTROL. 72 F.-

SUMMARY

AND CONCLUSION ~ 72 VI. . RECOMMENDATIONS. 75 A. PREOPERATIONAL NONRADIOLOGICAL' MONITORING STUDIES 75 B. OPERATIONAL NONRADIOLOGICAL MONITORING STUDIES 76 C. INTEGRATED IMPACT ASSESSMENTS 77

0. INTAKE / DISCHARGE DESIGN AND LOCATION 79 V I I .' REFERENCES 83 4

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vii i

'PART I INTRODUCTION In July 1980, the Environmental Engineering Branch, Division of Engineering, United States Nuclear ' Regulatory Commission (NRC), Washington, D.C. ,

initiated a review and assessment of nonradiological environmental operating data for ' three on-line nuclear generating stations. The three stations-selected were all located in midwestern, riverine habitats, so that the findings of _the review and assessment could be generalized and applied to other nuclear generating stations located in similar habitats. ,

The thtee stations considered in this report are Fort Calhoun Station, Unit 1, _ in Washington County, Nebraska; Cooper Nuclear Station, in Nemaha County, Nebt aska; . and Duane Arnold Energy Center (DAEC), Unit 1, in Linn County, Iowa. Fort Calhoun and Cooper Stations are located on the bank of Miss?uri River and utilize cooling systems of the once-through type, which withdraw water from, and discharge to, Missouri River. DAEC is located on Cedar River which is a tributary of Iowa River and utilizes forced-draf t evaporative cooling towers to dissipate waste' heat. Cooling system make-up water is withdrawn from, and discharged to, Cedar River.

Fo r t Calhoun Station has been in commercial operation since September 1973,

.uul produces a net electrical power -output of 475 megawatts (MW). Coo per Nuclear Station began commercial operation in July 1974, and produces 778 MW net of electrical power. ,DAEC began supplying electrical power to the Iowa

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Power Pool in May 1974, and generates 569 MW net of electrical power.

Given the length of time the three stations had been in operation, it was possible to provide, -in 'each case, an assessment of at least 5 years of operational data, to establish:

1. Whether the objectives of the monitoring programs had' been satisf ted.

2. The extent of environmental ef fects, causally related to plant operation, on the biotic groups as documented by analysis of operating data, t

3. Need for modifications to the programs to satisfy the program obj ec t ives .

The documentation format is arranged in a logical progresston which leads from historical and desertptive material to recommendattons addressing

' f uture pt ograms .

" art -11' includes summaries of station descriptions, biological

. characteristics.of the water' bodies under consideration, 4u+ major find ing s -

o f ' the three assessment doctanents.

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,e ll WK Part'III includes discussions;of those siting and design aspects of 'each -

, ' station' that directly influence the aquatic biota. - Topics covered include commercial and other uses of the rivers,. intake and discharge design and

.j .: . location' and cooling system design.

2

-Sampling methods used to ' assess aquatic biota at each site are reviewed in l' art IV, and critiques of the methodology are included. Complicating (f actors af fecting data analyses are discussed in this section.

Part V provides a comparison and contrast of the physical and operational-characteristics of the three nuclear generating stations considered herein.

Particular - emphasis is given to ZiT and discharge . temperature, intake volume

.and velecity, screen mesh size, . intata - and discharge design, and biofouling controls.

Recommendations on the form of future monitoring programs for aquatic biota in similar systems are addressed -in Part VI. These~ recommendations are based. solely on the findings from the three nuclear stations considered

hore, and can be applied to other sites only af ter caref ul consideration of .

tJhe,similsrities and dif ferences between the stations and aquatic systems involved.

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PART II STATION DESCRIPf10NS, IMPACTS, AND SUMMARIES OF FINDINGS A. FORT CALHOUN NUCLEAR STATION

1. Station Description Fort Calhoun Station, Unit 1, is located in Washington County,

• Nebraska, on the west bank of the Missouri River at abo ut River Mile (RM) 646. The station is approximately 20 miles NNW of Omaha and 3 miles south of Blair, Nebraska. The station has been in concercial operation since late 1973.

Fort Calhoun Station, Unit 1, is a 481-NW gross nuclear electrical generating station utitizing a once-through cooling systen. 'see Figure II-1). The cooling water is wi:hdrawn from and retusned to the Missouri River. In operation at reactor thetmal rating 9

1,420-MW,theplantrejegts3.3x10 BTU / hour to the condenser cooling water and 1 x 10 BTU / hour from miscellaneous bearing cooling and waste strerms (Ref. 1). Intake cooling water amounts to 360,000 gpm with a tit o f 18'F to 22*F. Maximum discharge temperature is 103*F in the 1973 to 1977 period. This temperature was extended to 105'F in the 1980 ETS. The station has a shoreline intake att ueture and a submerged discharge structure located downstream from the intake. The station operates according to the specifications of the Nebraska NPDES and NRC ETSs.

Data collected from 1974 to 1977 andic ited that the station utilized 1.5 to 2.5% of Missouri River flow and averaged 2.1%. Data on discharge velocity were not available. Furthermore, a detetuination could not be made concerning the status of 316(b) documents submitted to state and federal agencier by Omaha Public Power District (OPPD) in July 1977.

No biofoulang inhibitors of any kind are added to the intake waters (Ref. 2). The silt contents of the Missouri River water were reported as suf ficient to prevent biofouling of the cooling system; therefore, chlorination is not used at Fort Calhoun Station.

Chemicals are used in water treatment, liquid waste, sanitary waste, and decont.imination systems.

2. Characteristics of the Missouri River near Fort Calhoun Station The Missouri River is highly channelized, with relatively f ast-flowing water and high silt loads. Total' suspended solids in the river generally exceed 100 pat ts per million (ppm). The water flow is greatest during the mid- to late summer [ typically 33,000 to 35,000 cubic feet per second (cfs)). The river is ' impounded at v

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The fish community of the Missouri River is typical of those found in midwestern drainages (e.g., Ohio River), dominated by f reshwater drum, goldeye, carp, catfish, and suckers. Histortcally, fish spawning and feeding habitats have been reduced by dredging and channelization operattoas. The remaining habitats are primarily ,

tock revetment, pilings, wing dikes, and shallow, s ti t-s ub s t ra te embaynents.

The river has tributaries whici, provide suitable f tsh habitat. Weak commercial fisheries are believed to be sustained by larval fish input from these tributaries, The benthic community of the rtver appears to be influenced by the large fluctuations in water level, by channeltzation, and by maintenance dredging activities. River channelizatton has directly reduced benthic aquatic habitats which wauld otherwise be colonized.

The total nisnber of benthic taxa recovered during the 1971 to 1977 period varied annually from 53 to 70. Major components were cadd tsfly larvae (Trichoptera), mayfly naiads (Ephemeroptera), and larval dipterans (mostly chironomids).

The phytoplankton and periphytor. communities are typical of lotic systems, with dominant farns being diatoms, green algae, and blue gruen algae. Local dominance, however, is highly dependent on environmental conditions. Plant productivity is directly influenced by the high sitt 'oading of the river water.

3. Preoperatic.nal Projections of Station impacts The Fina? Environmental Statement (FES) for Fort Calhoun Nuclear Station, Unit 1 (Re f.1) presented potential environmental impac ts of station oper ation on the Missouri River aquatic biota. These impact projections were based on preoperational monitoring from 1972 to 1973 The FES concluded in its impac t projection (see pages i and ii):

" At times of high river temperature, fish will probably find tnat area (the zone where 2LT exceeds 5'F] unacceptable and avoid it.

The thermal plume is such that no barriers are expected which would teattict the upstream or downstream movements of fish," and "....no permanent papulation of benthic organisms is expected [to colonize the river's bottom near the flant]; however, some entrainment of passing dr if t organisms is anticipated. Even in the unlikely event of 100% mortality of these organisms during their 2-minute passage throigh the condenser cooling system, such mortality aiuld af fect only 3% of drif t organisms in the river at the plant location during 5

usual summer flow condittons and no more than 25% during unusually low river flow."

The following sections summarize arguments and projections of impacts presented in the Fort Calhoun FES: 3

a. Thermal Discharges (1) Fr eshwa ter . fishe s , including those of the Missouri River near Fort Calhoun Station, can detect temperature dif ference of less than 1*C, and generally will avoid the discharge zone when water tempetatures exceed organismic-preferred water temperature.

(2) No thermal barrier would be created, and fish movement upetreem and downstream w>uld not be interrupted. A temperature rise of 2.4*F will occur at the discharge during the summer perind, while the plume will occupy neacly 50% of the tiver width. The plume will also extend to a distance of 10,000 feet downstream f rom the plant outf all, rurthermore, the 5*F isotherms will only occupy 25% of the channel width, and will extend 2,000 feet downt iver f rom the outf all.

During the winter months, the rivet water temperature will rise by 2.5*F for the total rives width and will extend 5 miles downstream from the plant outf all. Neither summer not winter thermal conditions would create a thermal barrier.

(3) Fish are attracted to thermal dischatges during cold seasons. Rapid reduction in cooling water discharge temperature during these periods will result in mortality or thermal stresses to fish and other aquatic biota found in the mixing zonca. At For t Calhoun Station, fish may find watm water discharges attractive f rom December to Februaty when the Mtasouri Rivet water temperatures are lowe s t . Organisms that could suf fer cold shock near the station were teported to occupy a triangular zone which extends f rom the point of discharge to the eastern shore of the river (the oppostte shoreline) and for a distance of 1,000 to 1,200 yards downriver f rom the point of discharge.

b. Entrainment and impingement (1) Spring and early summer development of fish species in the Missouri River probably takes place in reservoirs located 6

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upstream from Fort Calhoun Station. Addittonal spawning -

and development were anticipated. to occur in chutes and 1 sloughs of the main river channel. (Chutes and stoughs are lacking near .the station.) Consequently, the station was predteted not to impact fish spawning grounds.

(2) A 2-minute exposure to elevated condenser cooling water temperature (/LT. = 18'F) is unlikely to seriously damage aquatic organisms passing through the condenser.

(3) Some; conditions will prevail when organisms in ;he plume become exposed to a ZiT greater than 5*F for 9 minutes.

(4) Survival of entrained fish larvae (e.g., carp, white catfish) at Fort Calhoun Station was projected to be low.

Mortality would probably be 83% within 2 days af ter entrainment (based on data obtained f rom Haddam Neck Station). .

(5) Several f actors govern impingement rates of juvenile and t adult fish among. which is intake screen approach velocity.

An approach. velocity of 1.0 f ps or less may limit fish imping ement. . Approach velocity for Fort Calhoun Station was expected to vary from 0.7 f ps to 1.1 f ps, depending on <

river flow conditions. An approach velocity of 0.75 fps will. minimize impingement for species such as wFite crappie i and channel catfish (based on fish swim speed). I (6) Due to high current ' speed in the Missouri River during sunser months- (4 to 6 fps), the zone of intake influence should be markedly less in summer than winter. This should  ;

be reflected in seasonal impingement (entrainment) rates.

c. Chemical Ef fluents Chemical ef fluents f rom station blowdown and sanitary treatment plants are not anticipated to pose any threat to existing

-aquatic biota in the river. These liquid ef fluents would contain such pollutants as chiarides, ansonium hydroxides, orthophosphates,. silica, and others in concentrations below those considered toxic to aquatic biota.

4. Observed and Measured Impacts The following sections -highlight .those impacts identified and measured by ESE during the 1973 to- 1978 operational . period. Changes and trends between the preoperational (1971. to 1973) and operational 4

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a. Phytoplankton and Periphyton l l

(1) By passing through Fort Calhoun Station coolinr, system, I phytoplankton of the Missouri River were reduced in abundance and changed in compos ttion only in July and August when A T was highest. Phytoplankt on and periphyton in the mixing zone experienced a moderate change of short dur ation in tespiratton, denetty, and chlorophyll a_

prod uc t ion. Phytoplankton and periphyton production is stimulated during tiie temainder of the year.

(2) In summer, carbon fixatton rate, chlorophyll a, and total density were generally lower at the Fort Calhoun Station point of discharge than at intake locations. Innediate ef fects of the discharge result in phytoplankt.on stress during the simmer. A decline in phytoplankton carbon fixation rate occurred when water temperatute exceeded 22*C (71.6*F); however, these parameters increased during the remainder of the year. In general, catbon fixation rate was inhibited during the summer, stimulated during the fall, and not affected for the temainder of the year.

(3) Phytoplankton ptoductivity index (carbon fixation per unit of chlorophyll a) indicated stimulation in winter, spring, and durier station shutdown, minot inhibition in sumner soon after entrainment, and no change in the fall .

(4) Diatoms that natur ally exist in the periphyton community upstream from the plant displayed little or no change at a distance of 2,000 f eet or more below the plant ottfall, while diatoms in the periphyton community at the outfall t egion were teplaced during hat periods by the mare temperature-tolerant, blue green algae. However, little natural substrates exist in the river.

(5) In genetal, no significant impac ts on phytoplankton wet e detected. On the contrary, a net inctease in phytoplankton abundance Was deemed to exist on an annual average.

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h. Zooplanktjg[

(1). Fort Calhaun Station eritrained 1.2 to 4.9% of the daily total Missouri River zoaplankton population passing the station.

(2) Impacts on zooplankton were judged to be minor and localized. ,

c. Benthic Mactoinvertebrates (1) A general. decline in the n inber. af taxa accurred during the study pertod, 'from 53 to 70 (in the preoperational period from 1971 to 1972) to 40 to 47 species (in the 1976 to 1977~

operational period) . There was an increase in species number from 61 to 77 in the 1974 to 1975 period.

(2) Benthic macroinvertebrates were nearly excluded fram Fort Calhoun Station point of discharge in the hot sunner months;

-however, benthic macroinvertebrate connuntty was judged to be healthy below the discharge. This was induced by elevated water temperature, since major taxa found in thic region are generally temperature sensitive. Na significant impacts could be attributed to the station during the remainder of the year.

d. Missouri River Fishes (1) Fishes of the Missauri River are . attracted to the Fort Calhoun Station outfall duri ng cold months. This was substantiated by the fact that abundance and ' diversity of fish collected at the discharge during periods of station operation were greater than those found at the same location during station shutdown periods. This is to be expected and - is commonly known for other stations.

(2) Fort Calhoun Station's operation does not influence fish feeding behavior of species such as goldeye and bass.

(3) Dtscharges from the station-do nat farm a barrier across the river and, thus, do not interrupt fish movements in the vicinity of the station.

(4) There is no evidence that Forc- Calhaun Station discharge is enhancing or detrimental to fisheries of the Missouri River.

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(5) . Fort Calhoun Station's discharge does not significantly impact commercial fisheries of the Missouri River in the vie tnity of the station,

e. .Entrainment

-(l) Fourteen to 21 species of larval fishes are subjected to

'entrainment at Pa r t Calhaun Station. Larvae entrained were dominated %y f reshwater drum, catostomids, carp, gizzard shad, saoger, and walleyes.

(2) Daily entrainment losses were estimated to vary from 119,000 to 12,280,000 larvae and averaged 2,960,000 larvae daily (this anounts to an average of 5.3% of the total river larvae passing the station, range is 1.8 to 12.8%).

Assuming a total of 77 days to represent seasonal (annual) entrainment, a larval mortality of 227,900,000 larvae is attributed to the station annually.

(3) Assuming a 0.1% survival rate from larvae to adult, a total "

of 227,900 fish'is lost to Fort Calhoun Station. This high ddult loss, however, is not reflected in the commercial fisheries landing. There has been no appreciable change in commercial fisheries. It seems likely that these larvac either do nat survive to adul thood or find their way to the Mississippt River. Lack of natural habitats plays a major role in larval mortality.

(4) Fart Calhaun Station does not signif tcantly impact ichthyaplankton of game fishes.

(5) Results of larval stud tes from 1974 to 1977 by OPPD o f ten >

indicated greater larval density at the intake. Far enample, in 1977, density of larvae near the intake (station 1) was nearly four times greater than at Station 2 (mid-river) and two times greater than at Location 4 (Iowa shoreline). In July 1978, larval density at Station I was 2.4 times greater than at Location 3 and 2.9 times greater than at Station 4. In July 1979, average larval density at Location I was five times-greater than at mtd-river and 2.2 times greater than near Iowa share (Station 4),

f. Impingement (1) A total of 46 fish species wa* imptnged at Fort Calhaun Station in the 1973 to 1977 period. Freshwater drum, gizzard shad, and channel catfish were among the species most of ten impinged during that pertod.

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(2) -Die station tmpinge ient mechanism was selective toward

- smaller fish. Fish impinged were generally less than 100 mm in length. Adult- fish were occasionally impinged.

These were mostly f reshwater drum and gizzard shad.

(3) The station displayed species selectivity toward freshwater dr um; however, it was nonselective toward gizzard shad.

(4) The impingement . rate was higher at night than during dayt tmc hours. This is not uncomuon and has been reported for power stations elsewhere. Impingement at night was estimated to be three times as high as it was during daytime hours.

(5) Fort Calhoun Static" impinged an estimated average of 139,925 fish annually and a maximum of 525,614 fish annually. This maximum represents a worst-case situation.

(6) When day / night dif ferences in impingement rate are considered, the station removed an estimated average of )

170,882 fish annually: 35,885 are f reshwater drum; 15,379 l are channel catfish; and 3,247 are flathead catfish. The  !

latter two species are commercially valuable in the region.

(7) The estimated number of fish impinged annually is very signtficant when compared to 1974,1975, and 1976 commercial catch data. However, no significant changes in commercial landings have been reported.

Fo r t Calhoun Station's operation results in the imping ement of high numbers of certain species of fishes, namely f reshwater drun, gizzard shad, and ch annel catfish.

However, this impingement does not seem to influence the commercial fisheries landing or the river fish population as evidenced in the available data.

The Missouri River has already been adversely impacted by dredging and channelization, and the commercial- fisheries on the river are small and r, m to be supported by present river larval input and recrut tment.

(8) Based on data evaluation, three major aspects df the intake and discharge are responsible for the localized effects as

.well as the high entrainment/ impingement rates. These are:

( a) At times, the plant operate, at a /LT that appears to be too high for biota tolerance in July and August.

This is a localized effect.

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l' (b) The plant operates. at an intake velocity (0.7 to 1.1

f ps, or greater) that is relatively high for smal t I

fish, particularly during low flow periods.

l (c) The plant has a shoreline intake. Shoreline intakes l generally exert greater tapacta on biota than offshore j or open-water intakes. Fur the nnare , the section of the Missouri River by the station's intake and from which 100%.of cooling water is withdrawn has the l highest density of organisms anong all stations. This I is particularly true for ichthyoplankton. Howev er ,

the river apparently receives a large amount of larval input in proportion to the small river fish pcpulation or the commercial fisheries on the river.

l (d) Bottom intakes exert greater influence on demersal species than pelagic species. Species such as channel catfish can easily be impinged at bottom intake screens, particularly the small specimens. This was

. demonstrated in the impingement of juvenile channel catfish in 1976. Because depth of cooling water withdrawal varies with river flow, the station's intake.may also act as surface or mid-water intake and thus, pelagic species become subjected to entrainment.

In summary, preoperational impacts projected were similar to operational (measured) impacts for general ef fects of the station's discharge. Projections on both entrainment and impingement dif fered f rom measured impacts by a large m arg in. For example, the FES indicated 3% mortality of drif t organisms during average summer flow (when fish larvae are available) . Estimates averaged 5.3% and reached as high as 12.8%.

5. Summary of Major Findings at Fort Calhoun Station Fort Calhoun Station, Unit 1, influences the aquatic biota of the Missouri River in the vicinity of the station in several ways. No signtficant adverse impacts on biota of the river could be directly attrtbuted to heated discharges from the station. Heated discharges from the station neither enhance the fisheries of the Missouri River nor do they provide good winter. fisheries as reported for other stations.

12

7' ,

. Fort Calhoun Station, Unit:1, removes an eatinated 227,900,000 fish  :

Liarvae and an unidentified number of fish eggs annually 'from the '

L Missouri River's ichthyoplankton commanity. Of the larvae -

entrained, an est'imated 227 " ; larvae were anticipated to survive .

co adulthood . if they had _ av Jed the intake, given that appropriate ecological conditions were 'available in the river. The majority of entrained -larvae were ~ identified as freshwater drum. The station does not. significantly : impact larvae of game fish. species but Lcould

~-

impact freshwater -drum and sucker populations. .This is assuming that appropriate habitats for these-fishes are 'found in the river, which might not be the case. Freshwater drum is a noncommercial s'pecies in' Missouri, and the sucker.is commercially valuable to the fisheries of the Missouri River.

Freshwater drum' and gizzard shad are impinged in large numbers by.

the station's traveling screens. There have been some potential losses due to impingement -of channel catfish and flathead catfish, both of which are commercially important in the region; however, it is uncertain if these fish could have survived and propagated in the

-river had they avoided the intake screens. Fort Calhoun Station impinged an estimated 170,882 fish annually in the 1973 to 1977 operational period, 29% of which were gizzard shad and 21% were f reshwater drum. An additional 9% and 1.9% of all fish impinged annually were channel cat fish and flathead cat fish, 'respectively.

The station impinged an unusually large number of channel catfish in' 1976. 1his high impingement cecurred only once since the ' station's operation began in late 1973.- However rare, there is no mechanism:

to prevent such an event f rom recurring in future years.

Significant adverse impacts of the station's operations to phytoplankton, periphyton, and benthic macroinvertebrate assemblages of the Missouri River were not detected in the ~1973 to 1977 operat tonal years. Minor ef fects on phytoplanktor. productivity .were noted during the warm summer months at the discharge location,-

however, this is of f set by phytoplankton stimulation at downriver stations, particularly 'in cool periods. Data on the zooplankton community indicated a lack of appreciable harm to that community.

B. . COOPER NUCLEAR STATION

1. Station Description Cooper Nuclear Station is located on the Nebraska side of the Missouri River at River Mile (RM) 532.5 The station utilizes a boiling; water reactor and ' steam turbine ~generater to produce 778 Ini (net) of electrical- power. The cooling system 'is a once-through design that withdraws water from, and discharges to. the Missouri ~

' 131

~

River (see Figure 11-2). Whenthegiant is operating at full load,

'the heat rejection rate is 5.6 x 10 RTU hour. Water is drawn into the station by four 162,750 gallons per-minute (gpm) capacity circulating pumps _(total: 651,000 gpm). The amount of water withdrawn is dependent upon the number of pumps in use. _However, the station utilizes an average of 2.2% of the river flow.

Chlorination of cooling water is not required for control of biofouling -at Cooper Nuclear Station because the silt load of the Missouri Rtver provides- suf ficient abrasion to prevent slime buildup. Chemicals are used in water treatment, liquid waste, sanitary waste, and decontaniuation systems. The station operates according to the spectfications of Nebraska NPDES and NRC ETSs.

During the period of warmer water temperature (June to September),

the Missouri River's ambient water temperature ranges from 61 to 83*F. Maximum plant discharge temperatures f rom Cooper Nuclear Station during the monitoring period from 1974 to 1978 was 103*F in July 1977 (Raf.3). Maximum temperature rise, /LT, measured at the station from 1974 to 1978, was 49.5'F in February 1977 (Ref. 4). A ,

g maximum discharge temperature of 103*F is reduced by dilution with receiving waters. The station has a /iT o f 18 to 22

• F. Data on

discharge velocity were not available. Furthermore, a determination

! - could not ce made concerning the status of 316(a) and 316(b) demonstrations submitted to state and federal agencies by NPPD in 1975.

i

2. Characteristics of the Missouri River Near Cooper Nuclear Station "

Biological communities of the Missouri River (including the plant site) have been subjected to various disturbances over the years, chiefly man-induced changes. As previously discussed for

~

Fort Calhoun Station, the. Missouri Rivet in the ' vicinity of _ Cooper .

Nuclear Station is wholly channeliz.sd. It consists of rock reectment along the shorelines and various channel tratning

sttuctures in the river. The tiver is dammed in several locations, and the main channel flow is maintained for navigation f rom March through November (Re f. 4) .

As previously stated in the description of the Fort Calhoun site, the composition of the biological community is generally typical of l large midwestern rivers. Some groups (notably, freshwater. mussels)

! are absent f rom the main channel of the Missouri River. This ebsence- is presumed to be related ta the unstable substrato- '

conditions found there. Other members of both the flora and faun'a l

{ 'that require stable substrates, in particular, are confined in o i occurrence to the limited back water habitats and. portions of. the l unchannelized river. .)

14-

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I SOURCE: 315 a and b DEMONSTRATION, NPPD, 1975.

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Figure 11-2 SITE CHARACTERISTICS AT COOPER NUCLEAR COOPER NUCLEAR STAT'ON STATION, BROWNVILLE, NEBRASKA 1

l l

15

p 3. Preoperational' Projections of Station impacts The Final Environmental Statement (FES) for Cooper Nuclear Statton (Re f. 4) discussed patential environmental impacts of station operation on thef Missouri River aquatic biota. These impact ptajections wete based on preoperational monitaring fram 1969 to 1973 (Ref. 5). .FES concluded in its impact projection that intake velocities of approximately 1.3 f ps across the intake acteen may L res ult in some loss of fish by entrainment or impingement. Biata l enttained in the cooling water will experience a substantial martality rate. Ilowever, lasses due to entrainment are expected to be small since only 4% af the river drif t _will normally be entrained during usual summer flaws. Worst-case prediction estimated a lass of 20% of the drift biota during unusually low flows.

The fal10 wing sections summarize projections of impacts pt'esented in the Caaper Nuclear Station FES:

a. Thermal Discharges (1) Freshwater fishes, including those of the Missauri River near Casper Nuclear Station, are sensitive to temperature and generally will avoid the discharge zone when water L2mperatures exceed arganismic preferred water temperature.

Convet sely, fish will be attracted to this warm water zone during the winter months.

l L (2) .During watm swumer months, watet tempet atures of the

! nearshare atea (for approximately 0.5 mile) below the -

discharge _will equal or exceed 93*F. The 90*F isothetm was predicted to extend downstream f ar nearly a mile. Because j of tiver conf tgutation downstream from Coopet Nuclear l Station, the plume will be restricted to the Nebraska shoreline. Th e zone was predicted to extend no more than j 200 feet from the shore during sunner and thus would not be l a barrier to fish movement.

(3) The effects of thermal loading on the aquatic oommunity in

l. general were pred teted to impact small areas during the s ummet period.

(4) Fish are attracted to thermal discharges during cold

seasens. Rapid reduction in cooling water discharge tem-perature during these periods will result in mortality or thermal ettesses to fish- and other aquatic biota found in the mixing zones. At Cooper Nuclear Station, fish may find

~

watm water -discharges attractive f rom December to February when Missouri River water tempetatures are lowest.

r 16

'l

b. Entrainment and Impingement (1) It was assumed for predictivu purposes that the nunber of drif ting . organisms entrained by Cooper Nuclear Station was in di et . proportion to the f ractiots of the . river flow used by the plant.

(2) Entrained organisms would be subjected' to an abrupt increase in temperature (approximately 18'f). The worst-case situation wauld occur during the cammer when entrained organisms wauld be subjected to elevated temperatures for av long as 20 minutes before leaving the discharge canal.

(3) It was anticipated that most, if not all, of the organisms subjected to entrainment during the sunener would be killed either by temperature or mechanical effects.

(4) Several f actars govern impingement rates of juvenile and adult fish, one of which is intake screen approach Approach velocity at Cooper Nuclear Station was velocity.

estimated to range from less than 2 fps to 2.5 f ps at low river flow. An approach velocity of 0.75 f ps wauld minimize impingement for some species such as white crappie and channel catfish (based on fish swim speed). However, it was concluded that any ftsh less than 3 toches long *,:at drif ted by the plant would be impinged on the screens and d ie.

(5) Since the totake structure is located an the region of high current velocities, not an area of regular habitat for small fish, it was concluded that numbers of fish lost are ins ign t f icant.

c. Chemical Ef fluents Chemical effluents from station water treatment and sanitary treatment plants were not anticipated to pose any threat to extsting aquatic htota in the river. These liquid ef fluents would contain such pollutants as chlorides, ammonium hydroxides ,

orthophosphates, silica, and others in concentrations below those considered toxic to aquatic biota.

4. Observed and Measured Impacts Summary and conclusions of operational impacts presented here are based on the findings of 5 years (1974 throtgh 1978) ot monitoring ef fects of Caoper Nuclear Station on the aquatic communities of .the

- - Missouri- River (Re f s. 6,7,8,9,10). Conc *.usions presented in this section are based on data interpretation by ESE for the- 1974 to 1978 period.

17

The measured impacts associated with station operation varied from the predicted in some instances:

e The magn. .ede of entrainment and impingement of larval f tsh and fish was un derestimated by the FES during periods of aver age sunmer flow losses. Th e se losses due to entrainment are expected to be v.sall. Ilowever, predictions during low flow perioda do not appear to be underestimated by the monitaring data, e Loss ef plankton and drif ting inse :ta tu entrainment is appatently wmall, and the FES prediction is supported by the data, e The loss of fish to cold shock remains an open question because ef lack of winter data, e The ef fects associated with the thermal effluent produced shif ts in the periphyton community. Iloweve r , the shift in dominance occurted between two diatom species rather than a shif t to h!ue green algae. Insects were apparently not eliminated f rom the theimally af fected areas,

a. Thetmal Impacts (1) River flow conditions and total plant production British 1hetmal Units (BTUs) dictate, to a large extent, the rmal pluno dimensions. Under most conditions of plant operatioas and river flow, the mixing zone extended to a distance of less than 2,000 f eet downriver from plant outfall, for the 5'F isotheim, and 3,240 feet down s t ream for the wtnter 10*F is > therm.

(2) The thermal pltne from Cooper Nuclear Station was shore-attached alonp the Nebraska shore. Excess temperature decreases rapidly in the first 1,000 feet downstream fram the discharge.

(3) Impacts on river fish populations were n ot detected.

Missouri River fish density in the vicii.ity of the station changed between years; however, species composition was relat ively stable.

(4) production of macrainvertebrates below the outf all was not I tmited by the addition of heat.

b. Enttainment and Impingement (1) Th e total intake screen impacts on the river fish conmunity amounted to the calculated removal of 484,859 fish 18

(July 1974 to December 1978) by unpingement (Refs.

6,7,8,9,10).

(2) Die majority of impinged fish' were young-of-the-year or yearling.

-(3) Generally, the patential number af harvestable fish lost to impingement was low in 1975,1976,1977, and 1978. In 1974, large numbers were impinged (see Table 11-1) . It was suggested that construction of the intake guide wall was respansible for this high impir.gement rate.

(4) Larvae of game and commercial fish species constituted a minor portion of the total entrained fish larvae.

Consequently, pacential impacts on game and commercial species were insignificant.

(5) Cooper Nuclear Station entrained 2.3 to 12.9% of all river larvac passing the plant. It was indicated that not all larvae entrained were killed, and various survival rates were estimated for larvae which passed through the condenser _ (Ref s. 6,7,8,9,10).

(6) Experience has shown that plant entrainment martality is attributed to a combination of thermal and mechanical effects.

In 1970, a meeting of concerned state and federal agencies resulted in a plan to investigate selected environmental ef fects associated with warm water discharges from Fort Calhaun and Cooper Nuclear Stations. The study' was divided into three major areas (periphyton and macrainvertebrates, fish , and chemical physical). Results of these agency studies are found in Hesse and Wallace, 1976 (Ref. 11) or Cada, 1977 (Re f.12) .

5. Summary of Major Findings at Cooper Nuclear Station Cooper Nuclear Station does not alter the phytaplankton, periphyton ,

zoaplankton, or benthic macroinvertebrate communities of the Missouri River. Some ef fects were noted for these groups, but they were confined to either minar seasonal differences or were spatially Itmited. For example, phytaplankton studies indicated slight

^

stimulation (within 7 haurs of exposure to plant) during the winter

~

and mknar inhibition of pr0duClivity dering the remainder of the year. Samples collected -fror the discharge canal provided some evidence of a shift in commun.iy. composition. . These changes , at t ime s , f avored the more tolerant green and blue-green algae over the diatoms but were not consistent enough, or of suf ficient-magnitude, to demonstrate major plant-related ef fects.

19

- ;3- .

1 4

- Table; II-1, Estimated annual fish- impingement at Cooper Nuclear Station, 1974 to 1978-

' Total Sample Size 1974 252,300 153 hours0.00177 days <br />0.0425 hours <br />2.529762e-4 weeks <br />5.82165e-5 months <br /> 1975 45,990 129 hours0.00149 days <br />0.0358 hours <br />2.132936e-4 weeks <br />4.90845e-5 months <br /> 1976 63,245 162 hours0.00188 days <br />0.045 hours <br />2.678571e-4 weeks <br />6.1641e-5 months <br /> 1977 40,296 233 hours0.0027 days <br />0.0647 hours <br />3.852513e-4 weeks <br />8.86565e-5 months <br />' 1978 83,028 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />

, TOTAL 484,859 704 houts a

v

Source

ESE, Compiled f rom Reference Document Numbers 6, 7, 8, 9, 4 . and 10-b 1

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s 20-I w w +e-*-- y tr- cw yay-w . ye d

r Cooper Nuclear Station entrained an estimated 0.9 to 6.5% of .the river zooplankton annually f rom 1974 through 1977. This calculation was based on plant water usage and the assumption of zooplankton homogeneity in the Missouri River (Ref.13).

-Based on a 4 year average, the plant entrained 2.9% of the river zoo plankton. This grand mean, however, is probably low since during 1977 there was a trend toward greater water usage as the station operated at higher turbine capacity (>84% on 8 of 12 sampling periods, Re f . 9 ) . Th us , an average calculated for 1977 only indicated that 3.7% of the' t iver zooplankton was entrained by Cooper Nuclear Station. This may represent a worst-case situation.

The station appears to heavily crop catostomid larvae by entrainment, but this loss is not reflected in the available commercial fisheries statistres. Large numbers of gizzard shad and freshwatet drum are impinged annually by Cooper Nuclear Station, bu6 neither of these species seem to be adversely affected. Bigmouth buf f alo populations could potentially suf fer losses, but as was the case with the other catastomids, commercial catches of bigmouth buf f alo did not seem to be af fected by station operation.

Cooper Nuclear Station does not interrupt fish movement in the Mtssouri River, and the plume does not form a blockade. Tagging stuiies conducted near Cooper and Fort Calhoun Nuclear Stations indicated random movement, with no apparent trends. Other studies -

have also indicated that fish will move in and out of thermal plumes.

Inspection of data for the October to November period suggested that gizzard shad, carp, and (to a lesser extent) goldeye were the species that would most likely be af fected by cold shock because these species appeared to congregate in the discharge canal.

No signiftcant adverse impac t s to the biota of the Missouri River f roin the Ccoper Nuclear Station discharge were detected. Localized ef fects in the' vicintty of the discharge have been observed. The se include changes in the diversity and productivity of phytoplankton, pertphyton, and benthic invertebrates at a certain time of the year.

The plant neither_ enhances the fisheries of the Missouri River nor does it provide good winter fisheries such as those reported elsewhere. Cooper Nuclear Station does not interrupt fish movement in the river..

C. DifANK ARNOLD ENERGY CENTER

1. Station Description Duane Arnold Energy Center (DAEC) is located in Linn County, Iowa ,

on the west bank of the Cedar River. The station is 8 miles 21

t-I-

northwest of Cedar Rapids and 2.5 miles north-northeast of Palo, Iowa.

l l DAEC is a nuclear generating station using a boiling water teactor to produce 1,658 megawatts .(Wdt) of heat and 569 megawatts (MWe) of net electrical output. Water for_ the closed-cycle cooling system is withdrawn f rom Cedar River,_ through the plant, and is pumped to f orced-draf t evaporative cooling towers (see Figure 11-3). 9At the design operating level, the plant dtssipates about 3.6 x 10 BTU / hour to the main condenser (95%) and restdual heat removal systems (5%).

A total of 11,000 gallons per minute (gpm) is pumped into DAEC from the river, which is 0.8% of average river flow. The net water consumption of 7,000 gpm is evaporated from the cooling towers, and 4,000 gpm are returned to the river as blowdown discharge with a Zi T o f 13.6 to 38. l*F. Maximum discharge temperature was 90.5'F through 1980. The station has a shoreline intake structure and a l submerged discharge att ucture located downstream from the intake.

Design discharge velocity is 6 f ps. Wells (1,500 gpm) supply demineraltzer makeup water, potable water, and water for att cooling systems. The station operates according to the spectfications of f the Iowa NPDES and NRC ETSs.

Ltquid chlorine is used as a biocide to prevent formation of bactertal slimes on heat-transfer surf aces. Chlorine is added to l

the circulating water at the condenser inlet for limited pertoda several times a day. Additional chemicals are used to regenerate l demineralizers for purifying plant water supplies, maintenance of water quality, corrosion inhibition, and cleaning.

ESE has been unable to determtne the status of the 316(a) and 316(b) pe rmit s .

2. Characteristics of the Cedar River near Duane Arnold Energy Center

! The Cedat River, in common with Iowa River and other rivers in the m idwe s t , is a nutrient-rich stream whose limnology is greatly influenced by agricultural activitica and hydrological conditions in the drainage basin, as well as discharges from municipalities and industries.

Due-to the extent of agricul tural runof f, the river contains ample uutrients for phytoplankton growth. Large fluctuations in runoff are frequent. Phytoplankton populations are reduced following heavy.

I rains when dilution occurs and turbidity is increased.

Createst abundances are notually present in spring and summer; concenttations above 100,000 units /ml are ~ f requently recorded during 22 i

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these seasons. A variety of diatoms, green algae, and blue-green algae have been reported in the river. One or more species of the genue Cyclotella is consistently the dominant organism in the phyta pl ankton. Blue-gteen algae, chiefly Oscillatoria, usually reach their greatest concentrations in July through September.

Abundances occur during the winter months, declining in fall with f alling water temperature.

Ratifers are normally the most nunerous companent of the zooplanktun in Cedar River. Cladocerans , copepods , insect larvae, and other groups are found in the river as well, but these larger forms are sparsely distributed. Detailed data on Cedar River zooplankton are not available.

Benthic populations in Cedar River near DAEC are generally limited in abundance and diversity, probably due to lack of suitable substrate rather than poor water qualtty. Most bottom areas are shif ting silt ar sand and, therefore, unsuitable far colonization by an abundant, diverse benthic community.

Areas near DAEC with mare f avatable substrates support populations of turbellarians (particularly a rhabdocoele near the genus Macrostomum) and midge larvae (chironomids). The mast abundant spectes of chironomids include Chernovskiia orbicus, Corynaneura i

sp., and Robackia clavigor. Gastropod and pelecypad molluscs can be abundant at ttmes.

l Carp and channel catfish are normally the most impor tant fish species in Cedar River near DAEC, due to their abundance and importance to fishermen. Carpauckers (river, quillba k, and highfin) are also nunerous. A variety of other suckers, as well as j

shiners, minnows, and sunf tshes, accur in the vicinity of the station. Walleye, sauger, pike, bass, and other game fish are uncommon in the area.

3. Pteoperational Projections of Station Impacts l

1 The Final Environmental Statement (FES) for DAEC (Ref.14) discussed potential environmental impacts of station operation on Cedar. River j aquatic biota. These impact predicitions were based on preoperational monitaring performed in 1971. The FES concluded in its tmpact projection (Pages i and ti) that:

.. a. Total residual chlarine in the discharge plume may reach 0.5 parts per million (ppm) periodically. The chlorine levels may prove toxic to river biota in local regions, particularly to fish attracted to the thermal plume in the winter.

24

1 m

b. Under worst . conditions, the temperature of the river wt11 be increased 2*F in a region less than 1 acre in surface area, and the plume will never extend beyand one quarter of the width of

~

the river. . Af ter mixing, the temperature of the river will increase not more then 1.1*F. This will cause a decrease of nat more. than 0.5 ppm dissolved oxygen.

c. Most biota passing through the intake screens will be killed.

Impingement is expected- to be minimal because of the low

(<0.75 fps) velocity at the screen. Less than 1% of the river will be diverted during average flows, and less thaa 10% will be dtverted during low flows.

The following sections present projections of impact which were presented in the DAEC FES:

a. Thermal Discharges (1) Below Mixing Zone. If complete mixing occurs, the blowdown water f rom DAEC will normally cause a 0.1 to 0.2*F temperature rise in the Cedar River below the mixing zone.

The maximum 4LT at historical low flows w3uld not excaed 1.1*F. Th is increase in water temperature over ambient temperature is not expected to have any danaging ef fect on rtver organisms, including f tsh. The decrease in concentration of dissolved cxygen associated with a 1.1*F increase in temperature is small (<0.5 ppm) in term + of the total dissolved oxygen in the cedar River (4.7 to 1o.5 ppm). This will have a negligible ef fect on river biota.

(2) Plume Effects. Depending on ambient conditions and season, some effects on fish may be observed before complete mixing of the thermal ef fluent with the river. These effects are discussed in the following paragraphs. The impact af these plume ef fects will be confined ta an area of less than 1 acre, with no. mare than 25% of the river width af fected.

(a) Winter Conditions. During periods of colder ambient river temperatures, fish may be attracted to the thermal plume, probably because of preferred temperature conditions and the improved availability of food. The strong discharge jet (6 fps) will prabably prevent most fish fram entering the warmest areas of the plume, and they will probably seek a zone o f preferred temperature where they can maintain themselves with minimal swimming ef fort.

25

The residence of fish in the heated effluent may have

~

the following consequences:

(1) Increased metabolic rate, causing decrease of condition factor (weight / length ratio). '

(2) Premature spawning, leading to loss of fry due to lack of proper food. Loss of some fry of white' sucker and sauger'(uncommon species in the Cedar River)' during the w!nter at DAEC is expected.

(3) Increased susceptibility to pesticides. Some fish species seem to be more susceptible to the lethal ef fects of pesticides with increasing temperatures.

The possibility exists that plume temperature may have a similar effect on species present in the Cedar -

River.

(4) cold shock in case of sudden plant shutdown. During a sudden plant shutdown, a drop in temperature to ambient will occur over a period of a few hours.

' Fish resident to the thermal plume. and acclimated to that temperature may be killed due' to the drop in temperature. This loss could not be avoided during an emergency shutdown. This situation, however, is remote. In other instances, cold shock can be prevented oy scheduling shutdowns for other than winter months, or by assuring that shutdowns are carried out over a period of days.

(5) Exposure to chlorine, leading to injury and/or death.

No problem is anticipated due to discharges of total chlorine up to 0.2 mg/l for a maximum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day, since the exposure times will be short and '

intermittent. In addition, carp and catfish appear to be relatively tolerant to chlorine concentrations.

Discharges greater than'O.2 mg/l total chlorine, however, may injure or kill fish attracted to the disch'arge by the warm water if they remain near the outfall. It is important, there fore , that chlorination be limited as much as possible during the winter months. Due to the colder intake water temperature and lack of agricultural runoff during the winter, the amount of chlorine needed in the intake water for slime control should be much less than that required during. the rest of the year. It is suggested that chlorination be performed only when a definite slime buildup is indicated, and that quantities be minimized and rigidly controlled.- If 26

total residual chlorine concentrations exceed 0.2 mg/l at the river discharge point, monitoring for symptoms of chlorine and chloramine-related damage to fish must be conducted and chlorine additions further limited if these kinds of damage are detected.

(b) Warm Weather Conditions Effects of thermal discharge on fish during the warner months are not expected to be as critical as during the winter. Cedar River fish in the area of the station will be free to seek their preferred tempera-tures. No fish should reach the discharge canal.

Some adverse ef fects that may possibly occur include:

(1) Increased incidence of fish diseases. Studies have indicated acceleration of certain diseases and the development of parasites in heated waters.

(2) Exposure to chlorine. It is expected that most fish will avoid the discharge plume when they sense a chlorine gradient, particularly in warm weather when warm water other than the discharge plume is available to them. The plume should not occupy a large portion of the river, even during low flow periods. Fish in the Cedar River may avoid concentrations of chlorine. However, it is possible that some fish, particularly fry, may not avoid chlorine concentrations; others may be present in the discharge area between chlorina-tion periods and be shocked by a sudden discharge of chlorine. Chlorine discharges less than 0.2 mg/l total chlorine should not harm adult fish during intermittent exposures, although fry of certain species may be sensitive.

(c) Effect on Biota Other Than Fish (1) Benthic Organisms. The blowdown water discharge jet is directed upward from the bottom, and s mixing with river water is so rapid that benthic organisms should exper ience little of the heated effluent except at the outfall. Although some local temperature increases will occur, various species of benthic organisms can tolerate considerable changes in temperature.

The benthic population in the Cedar River near DAEC is sparse because of shif ting sediments.

Scouring action and turbulence caused by the 27 L-

discharge jet will probably be the limiting factor in maintenanca of bentbos in that loca-tion, rather than the temperature. The destruc-tive ef fects of temperature and scouring will very likely be limited to about one quarter of an acre of the river bottom near the discharge pipe.

(2) Plankton. A portion of the phytoplankton and zooplankton in the river will drift into the warmed plume. The residence time in the plume will be relatively brief, and the temperature of the plume will rapidly decrease downstream.

Because of the small size of the plume and the relatively low temperature of the discharge water, damage to total phytoplankton and zooplankton populations in the river by heat is not anticipated.

b. Entrainment and Impingement (1) The intake velocity will be 0.3 fps at minimum river flow (less at higher flow rates). The intake structure is designed so that flow through the screens will be as uniform as possible at a velocity of < 0.75 fps to minimize tne entrainment and impingement of fish from Cedar River.

Most adult and juvenile fishes would then avoid being drawn into the traveling screens.

(2) Smaller planktonic organisms, primarily bacteria, phytoplankton , and zooplankton, will readily pass through the 3/16-inch mesh traveling screens and condensers. It can be assumed that most of these will be killed. However, plankton reproduces rapidly, and no species' population is likely to be perceptibly depcessed as a result of full power operation at DAEC. Furthermore, at normal river flow, less than 1% of the river water will be used by the plant.

(3) Most of the ichthyoplankton, as well as eggs and larvae of benthic forma, will be attached to or lying on the river bottem. They would thus not normally be subject to r.atrainment by DAEC. Only during record low flows would the river be diverted to the lower (weir) section of the barrier which spans the river, and thereby risk damage to river biota forced to pa:4 c.he outfall.

28

i r-

c. Chemical Effluents

' The only chemical discharge expected te be of potential harm to Cedar River biota is residual chlorine. It is toxic'to organisms in either its free _ or combined form. The Iowa NPDES permit specifies that free available chlorine must, average less than 0.2 mg/l and not exceed a maximum of 0.5 mg/l (Section 2.5). AEC (NRC) staff has established the following stricter guidelines for receiving streams in cases of intermittent chlorine utilization. Total residual chlorine may be <0.1' mg/l for a period of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day. This concentration should protect the fish species in the Cedar River. For continuous discharge, the concentration of total chlorine in the receiving stream must not exceed 0.005 mg/l to protect t,st warm water species of fish. This concentration would not protect some figh.

food organisms or sensitive life stages of certain fish species.

It should be noted that these guidelines are intended for the receiving stream. Concentrations of total chlorine below 0.1 mg/l cannot be reliably measured with present field methods.

In order to protece chlorine-gensitive organisms in the area of the outfall, the NRC staff holds the opinion that the 2-hour limit of 0.1 mg/l previously stated must be measured in the effluent before discharge to the river. During the remainder of the time, the limit for continuous discharge of 0.005 mg/l -

should be met. Since this concentration of total residual e chlorine cannot be reliably measured with present methods, ' -

IELPCo will only be required to ensure that total residual ( e chlorine in the blowdown is substantially below the limit of r' reliable analysis as detailed in the ETSs.

No free chlorine is expected to be present in the discharge to the river due to rapid reaction with oxidizable substances in the water. Combined compounds (particularly monochloramine) are expected to form in the cooling water due to the presence of '

ammonia in the Cedar River water which will react with the free chlorine. Concentrations of chloramine up to about 5 ppm are likely. Mixing of the water in the chlorinated condenser with water from the unchlorinated condenser will ' reduce the concentration of chlorine in the water by dilution and reaction r with chlorine-demanding substances. (Chlorine'will be added to half'of the condenser at a time.) But the extent which this r will reduce the total chlorine in the blowdown is presently not.

predictable due to the wide fluctuation in the chlorine demand of the water. Chlorine demand may rise to 15 ppm during early spring when maximum runoff from farmland occurs. If such runoff j contains high concentrations of ammonia, the concentration of .[

chloramine in the circulating water upstream of the cooling i

29

'S

'J ,

)-

tower will be higher. than the 5 ppm maximum previously stated.

/

f Because of uncertainty in expected levels of residual chlorine in the blowdown, IELPCo 'will be allowed an interim period in

/ which to determine whether total chlorine in the discharge to the riveh will exceed the reconsnended criteria at any time during the year. If this occurs, IELPCo must, within this

^

i interim period, determine the extent of the area in which chlorine in the river is detectable and must adopt an ecological monitoring program which will determine the effects of j.< chlorination on the' aquatic ecosystem. A limit of 0.5 mg/l

.,e

- total ch3orine in the discharge, for a period not to exceed

( ,2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day, is considered a maximum acceptable honcentration during this interim period. At all other times, totsi residual chlorine in the discharge must not exceed 0.1 mg/l during the interim period. These limits are based on the folicwing:

(1) Even with the historical 10-year low flow, these levels 7

will assure that af ter mixing (dilution factor of 20) total j residuct chlorins in the river will be 0.01 mg/1, or less,

,. except 'for a maximum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day when it may reach 0.05 mg/1'.

(2) The area of the river at the immediate outf all, in which the guidelines may be exceeded, will be relatively small in

, extent.

(3) Species of fish in the Cedar River are more tolerant of chlorine than cold water species such as salmon and trout.

Sensitive species of zooplankton and benthos, as well as sensitive stages of a particular fish species' life cycle, t

, may be adversely af fected by this discharge at the immediate outfall. Such ef fects are not expected to af fect the total river ecology. In the event that deleterious effects are found through the monitoring program, IELPCo

(

must reduce chlorine concentrations in the discharge as needed to protect the river's ecosystem.

In order to assure that plant operation does not result in s long-term adverse changes in the Cedar River, IELPCo must initiate a study of methods for chlorine control, if concentrations of total residual chlorine in the blowdown exceed

_'c ' the guidelines as stated previously. Within 12 months af ter

' , . . , startup, IELPCo will submit to the NRC staff a report stating

- , gr , , 4 hat it can,or cannot meet the limits established in the ETS.

~

.If it cannot, then a plan will also be submitted stating what

)

mc4(fications.IELPCo proposes to enable DAEC to meet the limits.

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^

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O

t. I

('

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30

v I

Stricter limits will be applied if required by Iowa State Standards or other applicable standards at that time.

Depression of phytoplankton photosynthesis and respiration may occur locally in the: plume area near DAEC as a result of chlorinated. discharges into the Cedar River. However, plankton productivity abould soon . recover downstream from the discharge xons, and not affect the total river ecosystem to any observable extent. The river monitoring program will determine whether there are any observable effects.

No other chemicals found in the blowdown discharge or the effluent from the sanitary treatment plant are expected to cause damage to river biota.

4. Observed and Measured Impacts The stemmary and conclusions of operational impacts presented in this section represent the findings of 7 years (1974 through 1980)

(Refs. 15,16,17-21) of monitoring effects of DAEC on the Cadar River aquatic community. These studies involved river populations of phytoplankton, periphyton, zooplankton, benthos, and fish, as well as fish impingement, entrainment, and live holding cage studies.

Conclusions presented in this section were based primarily on data interpretation appearint, in the Semi-Annual and Annual Environmental Reports prepared for IELPCO. Additional conclusions are based on independent evaluation and interpretation of available preoperational and operational data,

s. Discharge Impacts (1) Thermal plume dimensions are determined, to a large extent, by river flow conditions and total plant heat rejection.

The DAEC ETSs specify. that " temperature measurements in the river will be cade during representative low flow conditions (300 to 400 cfs) to verify the extent of the thermal pluma." Thermal pitne mapping was con iucted at least once each year from 1914 through 1978; the river flow did not drop below the minimum specified for plume mapp!ag during 1979 or 1980, and no mapping was done.

(2) Estimated area of the river subject to a lit of 5'F or

) greater ranged from less than 0.1 acre in 197L and 1978 to about 2.6 acres in 1977. During the worst-case conditions in 1977, river flow was very low at 283 cfs. The horizontal and vertical extent of.the thermal plume at that time can be estimated. The maximum extent of the 5'F excess isotherm was about 85 feet offshore, and for most of 31 m-

t r; -

4 *i Lits Llength the 5*F: isotherm rarely extended morej than 65

-feet offsho're. .The Cedar -River was 'approximately 200. feet

wide at this time, so that a substantial . portion of the -

. river's' widtli vaa available for fish passage. -A111 thermal' plume . mapping occurred during -the fall and winter when

~

~

river flows were lowest. Thermal blockage would be a potential problem'during warmer months, but Cedar River flows are reistively high then. -and the thermal . plume ..is

proportionately smaller.- Therefore.. no thermal blockage is . [

iexpected on the Cedar River due to the heated discharge -

from DAEC.

l l (3) : Det'ectable effects on Cedar River water quality due to DAEC operations were generally restricted .to Station 3,.

I immediately' downstream from the discharge. _ Biological- ,

. sampling and live holding cage' studies conducted upstream and downstream from the station demonstrated no consistent' -

! differences which could be attributed to chemical  !

properties of the blowdown discharge.

?

DAEC operational monitoring studies provided- some indication that fish were attracted to the' thermal plume during cold .,

j. months. However, no studies were implemented to address the

• i potential: deleterious ' effects listed previously, ro no ,

l conclusions:can be drawn'about the validity of FES predictions.

No sampling was conducted during cold season station shutdowns, r so cold ~ shock could not be evaluated. Results of fish cage-studies ~could not be used to evaluate potential chlorine-related

• ef fects, since during most of the study periods chlorination was ,

not occurring or chlorine was not measured. MDue inconsistency and sparseness of the benthic data obscured: any' potential

~

i station-related effects, if , in fac t ,' any . exis ted . No variations seen. in downstreem phytoplankton or zooplankton l population's could be attributed to effects of. station

[. operation. 1 i.

b. Entrainment and Impingement

_(1) Based on daily trash basket counts representing the number  !

l of fish collected over a 24-hour period,1a total'of 2,426

! fish war impinged during the period ' from plant startup in -

1974 through 198r Exclusive 'of 1974, ' for which- data were incomplete, an average of 402- fish were impinged on- the l DAEC intake screens each year. ,

\

(2) Young-of-the year (YOY) channel catfish and various minnow '

• i species- comprised most of the' impinged individuals.

1

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l l'

l

+

32

, + ~. > - , , ,

(3) Given the low percentage af Cedar River ficw utilized by DAEC and the small number of fish impinged, the problem of impingement ie no'_ considered serious at DAEC.

(4) Entrainment studies have been insufficient to address impacts on ichthyoplankton populations of the Cedar River.

However, based on the low percentage of river water utilized by the station for cooling. purposes, the level of impact is probably minimal.

(5) Phytoplankton and zooplankton populations in the Cedar River are probably not affected by entrainment at DAEC due to the low percentage of river water used by the station.

Statements in DAEC FES indicate that, due to intake design, most adult and juvenile fishes would- av sid being drawn into the traveling screens. The sparra distribution of macroinverte-brates in the water column led to the judgment that their possible entrainment and loss would be negligible. Any phyto-plankton or zooplankton drawn into the cooling system were assumed to be killed, regardless of species. Due to the high rate of plankton reproduction and the small percentage of river water used by the station (normally less than 1%), it was judged that no perceptible harm would be done to plankton populations.

Meroplankton and ichthyoplankton were expected to be sparse, since 'i.he majority of eggs and larvae of fish and invertebrates are anchored to substrates or lie on the river bottom.

_ Analysis of operational data indicates that FES predictions were valid. An average of only 402 fish per year were impinged on the traveling screens between 1975 and 1920. Entrainnent studies demonstrated very low abundances of fish eggs and larvae and planktonic macroinvertebrates. No apparent changes in phytoplankton and zooplankton populations were noted that could be attributed to station-related effects, instead of natural variation.

5. Summary of Major Findings at Duane Arnold Energy Center Much of the data collecting and reporting for most of the opera-tronal aquatic ecology studies were inconsistent and often deficient (see Part IV, C). Despite this circumstance, it is expected that major catastrophic effects on the aquatic biota due to impacts of I

station operation would have been detected by the monitoring

) program. DAEC does not appear to cause 'any major, long-term changes in populations of phytoplankton, periphyton, zooplankton, benthic

/ macroinvertebrates, or fish in the Cedar River.

33

An.cvercge of 402 fish per year was impinged on the traveling mereens-between 1975 and 1980. Based on quarterly 24-hour trash basket counts, most of the impinged individuals were channel catfish. Three fish eggs and 13 fish ~1arvae were collected during entrainment studies from 1974 to 1980. Eleven of the larvae were suckers of one or more species.

The blowdown discharge 'from DAEC does not stretch across the width of the Cedar. River, - and, therefore, it-does'not form a barrier to

. fish movement'.

There were indications that carp amd carpsuckers may concentrate near the discharge during the fall. Studies on cold shock effects were not L conducted in the winter; however, based on experience at other. stations, fish attraction to the heated discharge is anticipated.

Effects of residual chlorine on Cedar River biota could not be evaluated based on .recults of fish cage studies, vaunt these studies were done, chlorination of the cooling water was not occurring or chlorine coacentrations were not measured.

l t

1 134' -

I' l

s PART III SIT!NG AND DESIGN 1

A. FORT CALHOUN STATION 1.. Siting

a. -Site Relative to Main' River Channel Fort Calhoun Station, Unit I, is sited along the western

. shoreline of the channelized Section II, between Sioux City, Iowa, and the mouth of the Platte River. Due to hydrologic features of this portion of the river, the drif ting planktonic organisms, particularly fish larvae, tend to be concentrated near' the side of the river on which the station is located

- (Ref. 22). This may contribute to increased ichthyoplankton entrainment (Ref. 23).- If the station had been located along the eastern shore of this . river, ichthyoplankton entrainment would probably have been reduced below that experienced to date by as much as 50% or more. For example, larval density at the intake in 1977,1978, and 1979 was greater than that found near the Iowa shore by a factor of 2, 2.9, and 2.2, respectively.

b. Local Commercial Usage of the Missouri River The commercial fisheries of the Missouri River in Segments I, II, and III (between Platte River and Kansas City) do not seem to concentrate in any particular section within a segment.

However, if one considers the number of permits per river mile, it appears that there are more fishermen per river mile in Segment II than in both Segments I (between Yankton and Sioux City) and III. For example, in 1976, river miles fished in I- Segments I, II, and III were 81,138, and 105 miles, respectively (Ref. 24). The corresponding number of commercial permits issued was 40,115, and 52, respectively. Assuming each commercial permit represents either a single fishing boat or a fisherman, it appears that each boat or fisherman fished L

approximately 2, 1.2,'and 2 river miles in Segments I, II, and III, respectively. It follows that Segment II is having more fishing pressure per river mile than either Segments I or III.

Although the number of permits is used here to represent a measure of fishing ef fort, the sizes and capabilities of the fishing craft are not known,

c. Local Recreational Usage of the Missouri River The location of Fort Calhoun Station does not appear to interfere with recreational usage of the river. The station has

-potential for providing recreational winter fisheries. These, however, require access to the ' area influenced by the warm water outfall.

-35 t

During an interview in August 1980, staff of the Nebraska Game and Parks Commission indicated that future intensive recreational usage of the river is expected. Reasons for this projection were:

(1) More people are traveling to the eastern sector of the state of Nebraska where recreational water sources are located.

(2) The existing population centers (e.g., Omaha and Lincoln) ,

are in need of more water-based recreational activities, and the Nebraska River has the largest potential to fulfill these needs.

Within the context of the above, the station should not impact recreational usage to any significant degree.

d. Other Intakes and Discharges

, There are several water intakes located on the Missouri River j both upstream of Fort Calhoun Station (e.g., Omaha Station) and downstream (e.g., Cooper Nuclear Station). The presence of several water intakes on the river makes it imperative that:

(1) Impacts of Fort Calhoun Station on the Missouri River biota-must be considered in combination with the other intakes.

(2) The location of the other new intakes must be assessed at time of siting the station.

.Both of these two criteria are beyond the scope of this document but should be considered for future usage of the river. For example, impacts of the intake and discharge of Fort Calhoun Station were censidered to be minor and insignificant. However, the combined effects of the intakes located on the river (including Fort Calhoun Station's intake) could be of significant magnitude and have subtle, long-term consequences.

Fort Calhoun Station's intake results in the entrainment of an estimated 227,900,000 fish larvae and the impingement of approximately 170,882 fish annually. If these losses continue annually cnd similar losses occur at all stations downstream from Fort Calhoun Station, fisheries of the river (Segments II and III) could be severely reduced, unless additional fish and larval input into the river takes place or unless a compensatory mechanism is functioning.

f a

36 s

2. Design

a. Intake Location and Structure Fort Calhoun Station, Unit 1, has a shoreline intake structure extending 80 feet along the western shore of the Missouri River (see Part II, Figure II-1). The design and location of the structure allows water to enter the station from the section of

) the river closest to the intake (Ref. 23) . At normal water l

level (approximately 992.0 feet elevation), the major component of the cooling water entering the plant is withdrawn from the deep water with proportionately less water withdrawn from higher portions in the water column (see Figure III-1).

f l The location of Fort Calhoun Station's intake structure has bot'h

} ndvantages and disadvantages with regard to adverse l environmental impacts. Advantages includt:

(1) The intake is located in an area that lacks fish spawning grounds.

(2) Its present location (and design) may assist flushing along the shoreline.

Disadvantages include:

(1) The intake is located in an area where aquatic life (plankton and ichthyoplankton) concentrate (due to the river's hydrologic characteristics) .

(2) Most of the intake water is withdrawn from the bottom of the water column. Under average river flow, the depth of water intake will vary seasonally; thus, a multi-level intake (especially for once-through cycle plants) in this situation would be more environmentally sound than the existing intake design. By so doing, dif ferent areas of the water column could be avoided at times of the year when sensitive organisms (e.g. , larval fish and young-of-the-year) are present.

I b. Intake Velocity k The intake velocity at Fort Calhoun Station is directly related I

to the Missouri River water level. At high water levels, the intake water flows from the intake forebays to the screens with an approximate velocity of 0.7 fps. At low water level, the approximate intake velocity is 1.1 fps.

mm The U.S. Environmental Protection Agency (1973) (Ref. 25) has recommended reducing intake velocity to below 0.5 fps at the trash rack to enable fish to avoid impingement. NRC (Ref. 26) has recommended the maximum acceptable approach velocities to be approximately 0.5 fps. The U.S. Fish and Wildlife Service's 37

i ll ll

- -SCREEN

. SPLASH HOUSING

^

EL 1 -FL,00R i yTRASH TROUGH L. - -

I.---CURTAIN WALL

-TRASH RACK

""N ,e L O EEVEL EL 9.-

Q LOW WATER y ( LEVEL EL 983' 0*

/

O

. > c

/ L \ I EL 970* 0" CIRC. WATER PUMP \ l -

' SLUICE GATE SLUICE GATE TRAVEL NG OPENING

)

i l

CRIRCF OM AHA PUBLIC POWFR DISTR 1rT 1977 Figure 111-1 ""'

FORT CALHOUN STATION UNIT 1 INTAKE STRUCTURE DEPICTING CURTAIN WALLS FORT CALHOUN STAflON 1 AND SLUICE GATE OPENINGS 38

(1974) (Ref. 27) concern regarding intake velocity is reflected in the statement, "The maximum velocity protecting most small fish is 0.5 fpe, but even lower velocities will entrain larvae and plankton and even small fish where intake channele are not provided with an ef fective bypass.

c. Intake Screens Fort Calhoun Station utilizes standard 3/8-inch square mesh size traveling screens. Each screen is 8 feet wide with a continuous belt of 2.5-foot high panels. Screens are normally stationary

}

unless clogging becomes a problem, in which case screens are rotated and backwashed under a nozzle pressure of 100 pounds per square inch (psi). Washed materials (including impinged fish) flow to screen wash troughs which discharge back to the river at the downstream end of the intake structure. Water is drawn into the intake by three 120,000 gpm capacity circulating water pumps. Each pump draws water through two inlet bays.

The screen mesh size, in order to minimize impacts, should be a function of the size of fish to be screened. In current practice, the power plant industry has beenme generally standardized with a 3/8-inch mesh size scrt en.

Based on length frequency data of the dominant fish species impinged at Fort Calhoun Station, the 3/8-inch mesh size is adequate to screen moat impingement prone f ' ,h ( yo ung-o f-the year, juveniles, and adults) at the site. Howevet, in order to minimize entrainment of fish larvae, a fine-mesh screen (e.g. ,1 or 2 mm) would be necessary. This represents the present " state of the art". Given the physical characteristics and the suspended solid load of the Missouri River and the volume of the cooling water, these fine-mesh screens would become prohibitive.

d. Open- Versus Closed-Cycle Cooling Fort Calhoun Station uses once-through cooling (open-cycle system) to dissipate waste heat from the plant condenser and the auxiliary cooling systems.

A once-through cooling system for a power plant utilizes substantially more water for cooling than a closed-cycle system for a similar generating capacity. Due to the large volume of g cooling water necessary, open-cycle units tend to impose greater potential impacts (Ref. 28) . Howear environmentally attractive I

a closed-cycle system may appear, it may not necessarily represent the best r.vailable technology. A more sound app roach to minimize impacts of power stations on important aquatic resources would be to site the plant ir. areas where aquatic 0 resources are minimal to scarce (Ref. 29).

39

e. Discharge Location and Structure Heated water is returned to the Missouri River via a submerged discharge tunnel located approximately 60 feet downstream of the intake structure (see Figure III-1).

The discharge tunnel is rectangular and has a sloped face. It extends approximately 30 feet into the river. The tunnel's center line marks a 57' angle with the downstream shoreline.

This seems to deflect the heated water into a downstream direction.

The discharge is located at a distance adequate to prevent recirculation, thus reducing the probability of re-entrainment and enhanced impingement. An on-site station visit in August 1980 and a second visit to the area in January 1981 revealed no recirculation problems. The river flow was swift enough during January to prevent recirculating of the discharged water. It should be noted that the circulating water system is designed to allow the option of recirculation of heated discharge during the cold months (tempering) in order to minimize ice formatica on and near the intake structure and the traveling screens.

f. Mixing Zone Fort Calhoun Station does not have an extensive thermal plume.

Under most flow regimes and average power generating conditions (assumed to be 80 to 88% capacity), complete vertical mixing occurs at 2,000 feet downstream of the discharge (Ref. 30). The station's thermal effluent, perhaps due to fast river flow, seems to " hug" the western shoreline and rapidly dissipates.

Under average flow conditions the plume width is about 100 feet wide (1*F isotherms). During cold winters when the river flow is 20,000 to 26,000 cfs, floating ice significantly reduces the thermal plume dimension.

B. COOPER NUCLEAR STATION

1. Siting

a. Site Relative to Main River Channel Cooper Nuclear Station is located on the channelized main-stem of the Missouri River. Beginning in 1912, the lower portion of [

the river, from Kansas City to the mouth, was altered to permit maintenance of a 6-foot deep channel. In 1927, channelization -Y was extended to Sioux City, and, in 1945, a navigation channel j depth of nine feet was authorized.

Cooper Nuclear Station is located on the western bank of the river on the outside of a benJ This element of the siting g presents a biological problem. Hydrologic forces tend to 40

r:

concentrate planktonic organisms, including fish larvae, along this outside-bend near the station's intake, thus increasing the I chances for entrainment (Ref. - 9) . If the station's intake had l been located elsewhere, the entrainment potential vould have been decreased. Both entrainment and impingement would have decreased had that location been biologically least sensitive,

b. Local Commercial Usage of the River Commercial usage of the Missouri River generally consists of barge tous, commercial fishing, trapping, and assorted uses for i

cooling. The station's operation does not interfere with any of these uses. Conversely, the operation of barge tows apparently does limit the design possibilities for power station intake structures. This limitation necessitates a shoreline or very i near-shore structure because of the relatively narrow channel to ensure that navigation is not obstructed. Use of the river in Segment III by commercial fishermen is apparently limited, based on data for 1976 (Ref. 31). This use is apparently neither impeded nor improved by Cooper Nuclear Station.

c. Local Recreational Usage of the River One of several important considerations in evaluating potential impacts of Cooper Nuclear Station operation on the Missouri River is the availability and suitability of the area to recreational fisheries. Presently, the channelized Missouri River seems to be utilized by small numbers of fishcrmen. The 1979 State Comprehensive Outdoor Recreation Plan (SCORP) predicts increased usage for this region of the state (Ref. 32).

Indian Cave State Park, located 35 miles south-southeast of Cooper Nuclear Station, is currently imder development and is expected to become a major recreational facility. This develop-ment may be expected to increase pleast'.re craf t usage near Cooper Nuclear Station. Except for the small amount of river bank that is "off limita" because of security reasons, Cooper Nuclear Station's siting does not appear to have af fected recreational use of the river. A winter fishery in the area of the discharge could be developed by NPPD if adequate security could be maintained by a reasonable effort.

d. Other Intakes and Discharges

)'

! The Missouri River from Sioux City Iowa to Rulo, Nebraska, is presently utilized by more than a dozen major water users. Such g

users include municipal water supply, wastewater treatment, and p- power-plants.

I.

Cooper Nuclear Station is the last major water user upstream of Rulo, Nebraska. Analysis of the available data for Cooper Nuclear Station did not indicate any significant deleterious ef fects associated with plant operation. However, as previously 41

x 4

discu:ccd for' Fort Calhoun Station, system-wide impacts need to

beHconsidere'd for future usage of 'the river. The combined or cumulative' effects.of water usage, and subsequent entrainment

and ' impingement of fish -larvae and fish, may seriously affect the. fisheries of the lower Micsouri River. -For example, major water users, such as thv Cooper Nuclear Station, annually contribute to the loss of several million fish larvae. This impact' on the syster, may be somewhat offset in the future if

additional -fish habhat is provided -by the Fish and Wildlife Mitigation Plan _(Ref. 33).

2. Design

a. Inteke Location and Structore Cooper Nuclear Station -has a shoreline intake structure located q on the west side of the Missouri River at lower Brownville Bend (see Part II, Figure II-2). The intake structure was originally located flush with protective channel works. of the Corps of Engineers. In 1974, a guidewall was installed in front of the intake structure to reduce the amount of sediment being taken i into the plant (see Part II, Figure II-2).

l Water entering the station is apparently withdrawn from the entire water column. This was also observed during the statien visit in 1981. However, the proportional use of the water l: column is not known. The design of Cooper Nuclear Station's k

' intake structure appears to be disadvantageous with respect to.

minimizing the entrainment of larval fish. If the cooling water was withdrawn from near the bottom of the river, the number of l-I~

-larvae entrained would have been less. This conclusion is base 6 on distributional studies conducted near Cooper Nuclear Station in 1979 (Ref.10),

i l b. Intake Velocity l

Intake velocity at Cooper Nuclear Station is related to river water level. The higher the water level, the lower the intake velocity. Velocities at Cooper Nuclear Station were not measured directly but were calculated to range from <2 fps to l 2.5 fps at low water levels. These velocities are in' excess of those recommended (0.5 fps) by the U.S. Environmental- Protection Agency, Fish and Wildlife Service to protect small fish (Ref. 34).

c. Intake Screens Cooling water is drawn into the plant through eight screen bays.

- Large items and debris are prevented from entering the intake .

p bay by' fixed trach racks. The water-passes through traveling screens (1/8-inch mesh) and material retained by the screens is bsekwashed, collected in a trough, and returned to the river..via a discharge ~ pipe.- The use of smaller mesh (e.g., 1 or 2 mm) screens would probably mitigate some of the entrainment effects.

However, the use of these screens.may not be practical for'use 42

^

on the Missouri River because of probleris associated' with the 1 high silt load.-

'd. Open Versus Closed-Cycle Cooling Cooper Nuclear Station uses once-through cooling to dissipate waste heat from the station's condenser. The larger volume of water required by-once-through (open cycle) operations can pose several biological problems. The major. problems observed have-been associated with entrainment and impingement of fish and larger macroinvertebrates. Alternativc= include the use of

)- ' closed systems (e.g. , cooling towers) or careful' plant- siting prior to construction. If care is -exercised in siting the

' intake structure, the biological consequences of cooling water withdrawal can be minimized and the less expensive open-cycle t' raode utilized. Retrofitting Cooper Nuclear Statior. with a type of closed-cycle system does not appear to be justified. Future stations planned for operation on the Missouri River will require careful siting, and closed-cycle syatems may have to be considered.

e. Discharge Location and Structure Heated water leaving Cooper Nuclear Station is discharged into the Missouri River via a 1,000-foot long discharge canal (see Part II, Figure 11-2). The discharge canal is situated at approximately a 60* angle to the shoreline. The canal enters the river at a suf ficient distance downstream from the intake to preclude the possibility of re-entrainment of drifting organisms. The discharge canal at Cooper Nuclear Station does not appear to present any significant problem of bio'.ogical consequence to the Missouri River. The length of the canal allows sufficient mixing; however, the canal could attract fish in the winter time. During winter periods of plant shutdown, this could result in cold shock,

f. Mixing Zone The plume for Cooper Nuclear Station remains along the Nebraska shoreline of the river. Water temperatures above ambient decrease rapidly in the 1,000 feet insnediately downstream of the discharge canal. The size (laterally and werticitily) of the mixing zone does not appear to form a blockade to fish movement i upstream.

C. DUAN'd ARNOLD ENERGY CENTER

1. Siting

a. Site Relative to Main River Channel DAEC is located on the west bank of the Cedar River, Iowa (see l-Figure III-2). The channel in the reach next to the station is relatively straight; effects such as uneven scouring and siltation on either side of the streca are not known. *n i addition, planktonic crustaceans, fish eggs,z and larvae would 43-W

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MINNESOTA 3

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Waterloo Dubuque SITE #+ 4 1

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) Cedar Rapid 4

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ILLINOIS

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l KANSAS i

SOURCE: MODIFIED FROM REFERENCE DOCUMENT NO. 21.

Figure ill-2 DUANE ARNOLD LOCATION MAP: DUANE ARNOLD ENERGY CENTER ENERGY CENTER I

44

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, i unot be expected to concentrate nearer one bank than snother due j to hydrodynamic forces associated.with a curved channel, j The Ced"r River is the largest tributary of the Iowa River 'and I is fed from a well-defined drainage area' which at the mouth of '

the Cedar River is 7,819 square miles in area. There are 15 low-head dams on streams within the Cedar River bcsin,12 of which are located upstream of the plant site. Of these twelve, seven are actually . located on the Cedar River and five are located on tributary streams. The dams all have small impoundments and are not used for stream flow regulation.

)

b. Local Commerciat Usage of Cedar River I '- The Cedar River in the vicinity of DAEC is not used for either commercia1 ' navigation or commercial fishing. Some pleasure boating exists but it is principally confined to reaches downstream from the site, so river traffic in the vicinity of the plant is extremely limited,

c. Local Recreational Ussge of Cedar River Relative to DAEC, the Iowa State Conservation Commission (SCC) has built Pleasant Creek Reservoir, which has a surface area of (1.9 x abgut 10 feet 44g).

acres The and a storage reservoir is a capacity of 4,4 pumped-storage 50 acre facility feet approximately 100 feet above the river. The primary use of the reservoir is recreation, but Iowa Electric Light and Power Company (IELPCo) retains the option to release water from the reservoir to Cedar River, whenever river flow falls below 500 cfs, to make up for consumptive water use by DAEC. Pleasant Creek Reservoir is north of the station, close to Cedar River, and is not physically connected to DAEC cooling system.

d.. Other Intakes and Discharges

' Municipal and industrial wastes from the Cedar Falls-Waterloo area are discharged into the Cedar River upstream from DAEC.

- The ' distance from the Waterloo ' sewage outfall to DAEC ~ is about 35 miles. It is possible that this upstream source affects water quality in the vicinity of the station, particularly during low flow periods, but these discharges are probably of minor importance when compared to agricultural runoff.

The use of. Cedar River water downstream from DAEC is limited to supplying an indirect source of drinking water (via wells located near the river bank) and minimal recreational activities. The location of the site does not appear to result in deleterious effects on other uses of the river.

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2. Design

a. Intake Location and Structure DAEC intake is a shoreline structure located on the west bank of the Cedar River (see Figure III-2). A normally submerged barrier wall extends across che full width of the river at this point, with an overflow weir adjacent to the intake structure assuring availabi.ity of water in case of abnormally low river-flow water, is withdrawn from the entire water column.

b. Intake Velocity At minimum riverflow, intake velocity for the normal 11,000-gpm intake flow is about 0.3 fps at the entrance. At higher river- g flows, intake velocity is lower, because of the increased cross-sectional area at the intake opening. Maximan velocity through the traveling screens is about 0.75 fps. Based on impingement data from trash basket collections taken daily during operational years, the intake velocity at DAEC is accept-able. The low numbers of fish impinged (an average of 402 per year) are probably a very small percentage of the Cedar River total fish population.

c. Intake Screens The two traveling screens used at DAEC have 3/16-inch square mesh openings. The system includes an automatic wash cycle, during which debris is sluiced off the screens and collected in ,

a wire basket for inspecti)n and removal. A warm-water line from the circulating water system provides an optional de-icing spray at the grill inlet when conditions require it.

Based on available data, the re is apparently no reason to I recommind a smaller screen mesh opening to exclude ecologically, commercially, or recreationally important organisms tha t are '

presently being entrsined. There is no evidence that signifi-cant numbers of these animals are passing through DAEC traveling I screens. Presently available data are not sufficient to justify (

recommendation of a large mesh opening,

d. Open- Versus Closed-Cycle Cooling The DAEC uses a closed-cycle cooling system with forced-draf t cooling towers provided to dissipate waste heat. Water is I pumped into the station ut the rate of 11,000 gpm, which is less than 1% of average Cedar River flow, and less than 10% of low 0 flow. Roughly 7,000 gpm are lost as vapor from the cooling towers , depending on air conditions. The remaining 4,000 gpm are removed from the circulating system as cooling tower

" blowdown", in order to maintain a desirable dissolved mineral

(

46

concentration in the syr, tem. The water lost to the river (7,000 gpm) is less than 0.5% of average flow._ Once-through.

~

cooling is not feasible in a stream as small as Cedar River.

he possibility of building a' cooling lake as an alternative to a cooling tower was not evaluated; however, it warrants a closer look for.new generating stations.

l' e. Discharge Location and Structure Approximately_4,000 gpm of water purged from the circulating

(. water system are returned to Cedar River in the form of a

/ 15-inch discharge stream. The opening of the discharge pipe protrudes from the river bottom near the western shore, L immediately downstream from the intake. It is oriented so that the discharge occurs in the downstream direction at an angle of

{ 20' up from the bottom of the river. The design discharge velocity ia 6 fps. De discharge structure also includes an -

overflow weir which is above the level of the discharge pipe.

When flow in the discharge canal exceeds 4,000 gpu. (as might-occur during heavy rains), the water goes over the weir into the river through an open canal. Based on available data, the discharge system does not cause appreciable impact to Cedar River aquatic biota.

f. Mixing Zone Preoperational thermal plume analysis indicated ' that the maximum surface area of the Cedar River predicted to experience an

~

increase of 2*F over ambient water temperature would be 0.32 acre, during lowest flow in winter. The 5'F isotherm was predicted to cover an area o. . 037 acre under these same conditions. During warmer months and periods of higher river flow, the plume areas would be correspondingly smaller. It was predicted that the width of the thermal plume would not exceed 25% of total river width. Operational thermal plume mapping indicated that the extent of the mixing zone could exceed the preoperational predictions. The most extreme conditions were recorded in winter 1977, when an unusually low flow of 283 efs contributed to an estimated 2.6 acres of river being subjected to a 5'F AT. llowever, the maximtsu extent of the 5'F excess isotherm was about 85 feet offshore, and for most of its length, the 5'F isotherm rarely extended more than 65 feet of fshore.

The Cedar River was approximately 200 feet wide at this time, so that roughly 57% to 68% of the river's width experienced a AT less than 5'F, and was available for fish passage. Even under drastic conditions, then, thermal blockage should not be a

) problem in the Cedar River due to DAEC discharge.

47 i

Dirset mencur;mento of r20idual chierina in tha' diccharga plume were -not available for . analysis. Fish ' cage studies performed in the Cedar River near DAEC were not designed to examine specifically whether residual. chlorine could affect local fish populations.- Based- on thermal plume analysis, the area of the river likely to contain measurable levels of residual chlorine

~ is small. During most of. the year, fish should be _ able to avoid

. regions of perceptible chlorine concentration. During cold-periods, fish w',11 have a tendency to remain within' the mixing-

- zone, in the reg' ;n of elevated water temperature. They would

-. then be more. susceptible to the effects of chlorine. However,-

. less chlorine should be needed to control slime buildup in winter, due to colder intake water temperature and lack of agricultural _ runoff.

{

I 48

PART IV SAMPLING METHODOLOGY: REVIEW AND CRITIQUE A. FORT CALHOUN STATION

1. Phytoplankton Duplicate phytoplankton samples were collected twice monthly at the intake and discharge of Fort Calhoun Station. Intake samples were collected upstream of the intake. Surface water grab samples were composited and placed in 18-liter translucent carboys. Samples at the discharge were obtained by pumping water from the outfall into-a 38-liter cylinder-from which the duplicate carboys were filled.

Each composite sample was maintained in an environmental chamber at the intake water temperature and subjected to a light and dark cyr .e compatible with- normal day length at the time of collection for Jetermining carbon fixation rate.

Three subsamples from each composite water sample were analyzed for chlorophyll a concentrations at 7,. 24, 48, and 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> af ter collection. ~ Based on experience gained .from a large nember of electrical generating stations throughout the United States, the above methodology was judged adequate for the purpose of the study.

However, discrete samples should have been taken at the depth of water intake.

Periphyton samples were collected from glass slide artificial substrates both above and below (100 feet and 2,000 feet downstream from discharge) the thermal discharge site and directly in the area of the effluent discharge during the 1976 and 1977 investigations.

~

Artificial substrates allow for a standard

• zed method of comparison among periphytic communities found either above, below, or directly in the thermal discharge site. These comparisons are necessary in order to~ ascertain what effects, if any, the thermal discharge from Fort Calhoun Station have on primary productivity in the area of the discharge.

2. Periphyton Preoperational (1971 and 1972) periphyton studies involved the identification of only diatoms from glass slides samplers. During May through November 1971, six stations were sampled four times (Ref. 8). The 1974 operational studies of periphyton involved the collection and analyses of samples from August through November.

During this time, three sampling stations were represented by 14 collections each. These three station collections were taken at discharge locations above and below the station and were similar to those' stations sampled in 1971 and 1972 (referred to as FC-1, FC-2, j and FC-4, Ref 8).

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3. Zooplankton Duplicate samples were taken twice monthly with a filter pump system. Samples were collected from Location 1 at the station's intake'_ structure and Location 2 in the discharge tunnel. Intake samples generally _ were taken upstream of the surface sluice spray at a depth of 1 to 1.5 meter below the surface, depending on river l

stage. The filter pump system was equipped with Number 10 mesh (153-u) stainless-steel netting and Rockwell W-160 DR Turbometer.

Sample volumes ranged from 0.4 to 1.1 m3 , depending on the (

density of crustacean zooplankton, and were concentrated to 200 mi for analysis (Ref. 35) .

Frequency of sampling and methods of collections are adequate for the purpose of the monitoring program.

The use of a 153-u net is inadequate. F r one thing, it was unable to cietect the small zooplankton (64-u) organisms commonly found in fresh water thereby underestimating both abundance and species composition of the zooplankton comunity (rotifers and nauplii, U.S. EPA, 1973, Biological Field and Laboratory Methods). The use of 64 u and 505 u (or 202 u) is recomended specially for assessing the macrozooplankton community and thus its .importance as a food source. Larger zooplanktonic organisms possess the capability to avoid the 153-u net used in sampling.

4. Benthic Macroinvertebrates From the beginning of the preoperational investigations in 1971, rock baskets were used for the quantitative collection of macroin-vertebrates. Samplers were suspended for 21 days a few feet below the water surfact using anchors and floats. In the 1971,1972, and 1974 collections, all attached material on the metal basket in addition to the rock substrates were snalyzed. Beginning in 1975, only the standardized rock subgtrates wege sampled. The surface area of the rocks was 2,100 cm = 100 cm (approximately 2.25 square feet).

Samples were taken imediately upstream of the thermal effluent (at RM 646.0), imediately downstream from the effluent -(RM 645.8), and at stations located progressively further downstream from tr.e effluent, at RM 644.8, 641.4, and 640.2. All samples were teken (

monthly from April to November (from August to December in 1975).

Furthermore, a single sample was taken at each sampling station.

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'50

n v3 .

v J Thelovera11 samplingTprogram seems to be insufficient' .

~

While .

frequency of sampling!is judged adequate, the deficiency in the

- sampling program . is' due lto the following:

la.z JThe basket-type [ samplers, Jalthough more reliable - than 'others, .

are colonized by chance .(Ref. 36),f and there is no mechanism to prevent the organisms from leaving the basket once colonized.

Thus, only trend analyses over prolonhed periods aid the:

detection of major faunal cha ges in the river..

4 b. The samplers -osed 'can only be considered ' qualitative devices.

c. Lack-of replicates.

~d. .Only certain groups can . colonize the basket samplers. This-

. would necessitate ' the use of additional sampling gear (e.g.,

grab).particularly for infauna.

.5. Fish

. Adult and juvenile ' fish were collected from six Iccations in the ,

Missouri River near Fort Calhoun Station (see Figure IV-1). 'Three 'f major habitat types were sampled both upstream and downstream of

~

thefstation. The habitat type at Locations 3 and 5 on the Nebraska side 'of the river -included continuous revetment constructed of rock rip-rap and pilings. The current was swift and the bottom was scoured along' this 'outside bend of the river. The area sampled at Location.5 was within the zone of thermal influence from the-station.

- The second habitat type . included wing. dikes on the Iowa side of the river, with shallow, silt-bottomed embayments situated downstream of these structures (Locations 4 and 6) .' Outside the wing dikes, the. current was swift, and the substrate was scoured. In calm areas behind L the Twing dikes,' sand and slit had been deposited by .

eddy currents.

The third habitat type was the mid-channel area immediately above and below Fort Calhoun. Station (Locations 7:and 8). LThese locations were characterized'by deep water,-a swift current, and scoured bottom. They were ' sampled only during 1974 and 1975.-

' Electroshocking was conducted withL a 3-phase, 230-volt AC boat-

' mounted boom shocker at Locations 3, 4, 5, and 6. Approximately 1,200> meters of shoreline were sampled for. a ' period of approxi-

.mately 30 minutes at each. ir:ation.

i A seine, 7.6 meters'long and 1.8 meters deep, with-0.6-meter,' Ace mesh was used to ' sample shallow water areas at Locations 4 and 6.

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.s A.

One' to four seine hauls.were made behind a wing dike at each location.

The mid-channe. Locations 7 and 8 were sampled by drifting a trammelinet along the bottom of the channel in the mainstream. The net was 30.5 meters long and 1.8 meters deep, with a 3.8-centimeter bar mesh inner panel and a 15.2-centimeters bar mesh outer panel.

One net' drif t covering a distahce of about- 610 meters was made e during. each sampling; period. This gear was employed to collect species-that inhabit'the mainstream type of habitat. However, this

). technique proved to be dif ficult to use and was unproductive; consequently,=it was discontinued after.1975.

g Differences in sampling techniques between preoperational and f; postoperational years are summarized as follows:

a. . For preoperational: fish were collected from (1) along the trail dikes with electrofishing, and '(2) along the downstream bars behind wing' dikes with seines.  ;

b. For postoperational: (1) electrofishing along Nebraska and Iowa shores, (2) seines along Nebraska shores, and (3) trammel nets--mid-channel 1973 to 1975.

Generally, very few fish were caught from the river and we were unable to utilize the river fish data for assessing the impact of the intake structure (impingement). However, the sampling program was adequate for assessing the impact of the heated outfall and providing such parameters as presence-absence or general abundance.

The following applies . to the river fisheries program:

a. The change in the sampling program between preoperational and operational years prohibits quantitative (e.g., catch per effort) comparisons between the two periods,

b. Habitats sampled were not compatible.~ For example,. stations along the Iowa side of the river had fish habitats dissimilar to those along Nebraska shoreline.

c. Seining was done at Stations 4 and 6 only. Similar data were needed for at least the central station, Station'3.

d. Unfortunately, due to sampling difficulties, mid-channel  !

sampling was terminated in 1975.

e. There has not bean any indication that any attempt was made to use surface and bottom trawls.

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16.. Entraine:nt of Fich Egg 3 cud.Lcrvaa

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Larval" fish : samples .were collected with two Number 0 (571-u) mesh .

nitex plankton nets -suspended _ from booms' attached to each side of a

~

. boat'.. A . flow ' meter .(General Oceanics~ Model 2030) was attached in

. the mouth- of each net to determine the collection velocity. and _the volume- of: water sampled. i Samples were collected with 0.5-meter

diameter ' nets -in 1974 - and 1975 at s' collection duration of 3 to

, ?7 minutes. . In 1976 and 1977, . 0.75-meter diameter nets were employed and. collection duration was reduced to 1 to 3' minutes. ~

The larger. net and reduced collection duration were implemented in an' attempt to reduce collection mortality.and still maintain an

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" adequate. sample size. _In addition to the larger nets,in 1976,

. collection buckets were switched from screened.to unscreened.

buckets in an effort f to further reduce. collection mortality. All

~

entrainment and horizontal distribution samples were collected from '

.the upper meter of water, except at the discharge location, from-mid-June-1976 through 1977. In-1976, a frame was installed at the end of,the discharge' tunnel to-provide'a means-by which plankton

-nets could be lowered .over the discharge port. This allowed discrete samples-to be-collected from the discharge.

Duplicate samples were collected at each of six locations for

~

anal ~ysis of entrainment ef fecca from mid-April through early August 1974, 1975, and 1976. Samples were taken from the river biweekly-j in 1974 and weekly in 1975 to 1978.

Duplicate samples ~were collected at the discharge and plume loca "

tions, whereas eight . replicates were collected at the intake. The 4

- additional ' intake replicates were collected in an effort to deter-mine net-induced mortality.

The_ichthyoplankton (entrainment). sampling program has overlooked i' several characteristics related to both biota 'and to Fort Calhoun Station-itself._ For_ example, larvae were not sampled at night, a character which must be implemented in the entrainment program.

The following applies to the sampling program:

a. Samples were taken at or-near the surface while intake ,

water was drawn from the bottom of the water column. This would tend to overestIm' ate the entrainment impa,c t .

L b' . More sampling stations were needed near the intake since i fish larvae were concentrated 'along the Nebraska n

. shoreline, c.. . Biweekly sampling in 1973 and 1974 were insufficient to represent this period.

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d. Fish eggs-were not identified or counted until 1978.

e. Duplicate samples are not adequate in providing accurate estimates on the patchy fish eggs and larvae. This is particularly based on experience gained working ' on this trophic level .which indicate that significant differences could exist among the duplicate samples taken at the same time at the same place. However, difficulties associated with obtaining representative ichthyoplankton samples'from patchy distributions are acknowledged (Ref. 37) .

}

f .- A 0.5-meter diameter net used in 1974 and 1975 is inadequate. It has been reported (Ref. 29) that meter nets provide greater numbers of fish larvae (and greater size intervals) per . unit of volume than half meter nets.

I However, we acknowledge the need for site-specific gear tests (none was reported here).

7. Impingement of Juvenile and Adult Fish Daily impingement samples were collected at noon (;+ 2 hou: ) and at midnight (+ 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) from May through September 1973 through 1977.

Samples were taken at noon only from October through April of the same year. Fish were removed manually from the traveling screens for 60 minutes following cleaning of the screens. During each hourly sampling period, one of the 6 traveling screens was sampled on a rotational basis, i.e., each of the 6 screens was sampled once every 6 days. A total of 2,345 hourly samples was taken during 56-month study period.

In addition to hourly samples, 24-hour impingement studies were conducted on 29 occasions from 1974 through 1976 to determine diel impingement rates. All 6 screens were sampled during the 24-hour studies.

The impingement sampling program is inadequate due to the following reasons:

a. Sampling 1 screen every 6 days does not allow assessing variability between screens,

b. Annual impingement estimates, when based on hourly samples (mid-day and mid-night) most likely provide unreliable f estimates. These estimates could either underestimate or overestimate the actual ' impingement impact. Annual impingement estimates are based on extrapolation of monthly, daily, and hourly impingement. The longer the extrapolation process, the wider the margin of error. Furthermore, it seems unlikely that 55

r i

the . timing of these hourly. samples would coincide with cyclic

-behavior of fishes impinged.- If sampling were not to be conducted for 24~ hours, a major segment of the day would be considered.

Based on data presented in Reference Number 23 (data were taken at 2-hour Intervr.is for-24 hours in 1974 to 1976), it seems obvious that most fish were impinged between 0200 and 0800-hours and 1600 to 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />.

c. Sampling ef forts are nearly equally distributed throughout. the' year. More ef forts should be spent when fish are most (

active (Ref. 38) (e.g. , sprin'g ar d summer) .

d. Sampling-at 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> (diurnal) and again at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> j (nocturnal) could not be used to detect day-night differences in impingement rate (Ref.'23). This is substantiated by the.

fact that the hourly samples showed no significant dif ference.s in impingement rate between day and night but the daily (24-hour) samples showed night impingement rate.to exceed daytime impingement rate by a factor of three (Ref. 38).

e. .The 24-hour collections were taken monthly or biweekly. .A month is too long a period to be represented by a hour collection particularly at times when fish activity is high. A similar conclusion can be drawn regarding biweekly collections.

It thus follows that the possibility exists that high impinge-ment rates could have occurred between each two consecutive 24-hour sampling episodes,

f. The fact th a t the sampling time (mid-day and mid-night) was predetermined, the randomness of the data-gathering process was already eliminated.

8. Factors Affecting Data Analyses In process of Fort Calhoun Station's appraisal work, three dif ficult areas were encountered primarily because of either the sampling methodology employed or lack of suf ficient data base. Problems encountered were in the area of impingement, entrainment, and river

! fisheries. These complicating factors may have lead to overestimating 4 or underestimating the real impacts. The possibility exists that .when all factors are considered, they may have of fset each other's ef fects. ,

n. Impingement Data Because the impingement sampling program was conducted in a way so that not all screens were sampled at.the same time (i.e.,

during each hourly sampling period, one of the six traveling screens.was sampled on a rotational basis), the impingement estimates provided here accounted - for the statistical ~

56 l

differences between all screens. This method resulted in placing. wide confidence intervalo on the estimate.

Estimates of' annual impingement rate were based'on monthly extrapolations of impingement which in turn were based on hourly sampling at mid-day and at mid-night, two periods that

-do not seem to adequately represent fish activities.

Having extrapolated annual impingement from hourly collections enuld increase the margin of error in addition to the fact that these data could underestimate-annual impingement rate.

The 24-hour collections used to estimate the day-night dif ferences in impingement were too few and too widely spaced-in time to be used in estimating annual cropping _ of the intake.

b. Entrainment Data A complicating fsetor affecting entrainment data analyses was the fact that larval collections were made in-the river near the surface, while a portion of the plant's intake water was drawn from the bottom of the water column. Larval density could decline with depth, however, we do not have data (1975 through 1977) to substantiate that. No estimates were given on numoer of eggs entrained annually since data on fish eggs were not collected.

In estimating annual larval entrainment rate, data from May 14 (initiation of sampling) through July 29 (termination of sampling) of each of the years 1975,1976, and 1977, were _

considered representative and were used to estimate the-number of larvae entrained daily and annually. By integrating average daily losses over a 77-day period, the resultant estimate would represent total annual mortality. This method tends to underestimate the real mortality since larvae were found in the Missouri River as early as- April 8 and as late as August 18 (Ref. 39) (data for these additional periods were not -

available). -

'i In estimating entrainment rate, the assumption was made that all larvae entrained were considered lost. This assumption was

~

'3 primarily based on experience gained from other stations, "-

published data (Ref. 40), and the fact that viability studies -

to date are of short-term duration.

c. River Fisheries Data Fisheries data in the vicinity of' Fort Calhoun Station were not sufficient to relate to impingement data. Fisheries data used were those published by Nebraska Game and Parka Commission.

The accuracy and reliability of -these data.were not assessed.

57-N .'

7-

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J f j Without usiag fisheries data, the impingement impacts become meaningless.!

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I f, B. COOPERNUCLEAR/TATION

-(.

1. Phytoplankton

.,, I Duplicate phytoplankton samples were collected monthly from the b Missouri River near Cooper Nuclear Station. Samples were collected 1 meter below the surface with a nonmetallic water sampler.

Phytoplankton ' collections . began in 1970. The sampling program g could not realistically separate station effects from natural

1. 1 variation. A comprehensive study to measure station effects on phytoplankton would necessitate a very large and expensive program.

i The costs of 4 this comprehensive program may not be justified since I- ~

extensive c#,brience gained from other stations indicated that, j under a simil'or set of circumstances (e.g., large river, small edxing zone, e oling water is .a fraction of t.he river flow) impacts on phytoplanktan were not detected. Phytoplankton have a a generation timb of only few hours and thus, portions of the community inf1(enced by Cooper Nuclear Station could be replaced

. within a few mi.les downriver.

2. Pe r i phy ton,.

Y l

Periphytic algae was collected from artificial substrates suspended in the Missouri River. The artificial substrates consisted of I

plexiglas pistes. Collections were made monthly from June through i Novemberr ' Beginning in 1976, artificial substrates were placed in

j. the discherne canal as well as the river.

l' The overall samp1!,ng program for periphyton appeared to be well conceived. The sampling locations included an upstream reference

.: location and sate.cient number of downstream locations (3 to 4) to l

i. /

define the JatGrni extent of the area of biological effect related I

'tio ,the therma) discharge. The only shortcoming in the program was I the. lack of data'during the early spring period (March through I

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i r 1 M,ay).

y f- y <

g s

• l l ,

1.' Zooplankton

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/3 '

Duplicate zooplankton samples were collected monthly (May through November). Sam [les were collected with a Miller high-speed l

1. plankton samplen In 6ddition, zooplankton was sampled at the

~

l intake, dischange,' and 7,500 feet. downstream of the discharge.

These samples' ware collected with a modified Icanberry sampler and j were used to determing mortality due to station entrainment.

i

,g The methods and' Ne uency of zooplankton sampling were considered f accept Abb to med the objectises of the monitoring program. A b  ;\

/y er I\-

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i V }y < \ q

!5 7 / 4

'k> t j-:-l-}

< sa sy _

.. A v1 i, i; \ -

4

problem, common to both phytoplankton and zooplankton, is their known patchy distribution. Because of this highly vs.iable distribution, conclusively separating plant-related effects from natural variation is extremely difficult. Our experience has indicated increasing sampling frequency or years of monitoring may-not yield additional substantial information on these trophic levels.

4. Benthic Macroinvertebrates Benthic macroinvertebrates were collected from natural substrates t

from 1969 through 1978. In addition, artificial substrates were employed from 1972 through 1978. From 1972 thorugh 1974, rock  !

filled baskets were used; these samplers were replaced in 1975 by multiple plate samplers.

The methodology used to sample macroivertsbrates was generally adequate to meet the monitoring program equirements. However, the sampling frequency (threu time; annually) was judged to be less than adequate. At a minimur. quarterly sampling should be conducted. The sampling locations downstream from the discharge were spiced too far apart to detect the lateral area of major impact. Lastly, it is recommended that drif t net sampling be conducted when using artificial substrate samplers. These collections should be made at frequent intervals during the period of substrate colonization. A variety of sampling location configurations can be used to monitor the " natural" drif t of the river; drift associated with discharge canale; and drift associated with the mixing zone.

5. Fish Adult and juventia fish were collected near Cooper Nuclear Station by electroshocking and shoreline seines. Samples were collected monthly from May through November. Because of river level fluc tuat ior.s , the ef fort expended for seine collections varied between sampling crips.

Arriving at good estimates of fish populatione is a difficult task.

Generally, the sampling program for adult and juvenile fish was adequate to address the monitoring program requirements. However, data collection during this program was hampered because:

1. Physical difficulties associated with the Missouri River did not permit a uniform level of effort.

2. The sampling effort, and consquently the data, were restricted to two gear types.

59

3. The total lack of information for the winter period precluded making estimates of the number of fish that might be attracted to the plume and that could be subjected to cold shock.

6. Entrainment of Fish Larvae Ichthyoplankton entrainment by Cooper Nuclear Station was evaluated during the operational period from 1974 to 1978. In addition, a short-term ntudy was conducted .in June and July 1973 to assess the i effects of condenser passage without thermal loading. Sampling locations varied during the study but always included comparisons between the Nebraska and Missouri sides of the river. Samples were generally collected at the surface or within one meter of the (

surface. Larvae were sampled at varying intervals from May through July annually.

The use of multiple location cross-river transect sampling appears to produce the most useful information in systeme like the Missouri River. This sampling scheme, however, was not employed until relatively late in the monitoring program. Because of the seasonal nature of ichthyoplankton occurrence, a relatively intense progrem of study with replicated day and night sampling should be used as opposed to more limited data cotlected during this study.

7. Impingement of Fish Fish impingement data collections were begun in July 1974 The number of hours sampled varied by month and year as did the time of sampling (i.e., nocturnal versus diurnst). At Cooper Nuclear Station, the traveling screens are bac k flushed with high pressure water spray. The material washed from the screens is t ' -c ted in a common trough and carried to a pipe that discharges , 'erial back to the river. Impingement samples were collected f - rhe trough prior to entering the discharge pipe. Station personnel collected the samples and identified the fish.

Impingement sampling provided what may be generally relevent data to assess the relative impingement rate at Cooper Nuclear Station.

Sampling efforts ranged from 2 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per month '(see Table IV-1). Extrapolating monthly and annual impingement rates from such few points can result in large deviations from reality.

The effort expended to collect impingement samples should be increased for future monitoring programs, because the existing data are of questionable value.

8. Factors Af fecting Data Analyses The physical rigors of the Missouri River perhaps constitute the most important limitation to data acquisition and interpretation for 60

r Table .IV-1_ Sample periods '(hours) . for fish impingement campling at Cooper Nuclear Station,1974 to 1978 Day / Night' Total 1974 1975 1976 1977 1978 1

January ----

11/6 4/-- 8/10 1/1 17 4 18 2 j February' ----

7/5 1/3 10/10 0/2 l 12 4 20 2 March 2/0 1/2 4/3 11/12 2/1 2 3 7 23 3 April 3/1 14/8 10/12 10/11 0/2 4 22 22 21 2 May 12/4 11/8 5/5 11/11 1/1 16 17 10 22 2 June 12/6 6/6 8/9 11/11 1/1 18 12 17 22 2 July 13/6 2/5 10/12 10/9 0/2 19 7 22 19 2 August 14/8 2[3 a 11/12 8/12 0/3

+ 22 5 23 20 3 September _ 12/4 6/11 8/9 6 /_7_, .0/2 16 17 17 13 2 October 16/8 ---- ----

8/4- 1/1 24 12- 2 November 12/7 0/3 6/7 11/10. 0/3 19 3 13 _ 21 3 December 10/3 5/7 11/12 11/11 1/1 13 12 23 22 2  ;

-TOTALS 77/36 65/64 78/84 115/118 7/20 113 129 162 233 27 Source: ' ESE, Compiled from Reference Document- Numbers 6 through 10 61 3

l

-Cooper Nucicar Station. Other difficulties in the data sets involved changes in sampling gear, addition or deletion of sampling locations, and long intervals of time between the fall and spring s ampling ' period s.

Specifically, impingement rates were calcualted from a varying number of observations. The estimates provided by this method were subject to a good deal of variation. More trequent impinFement sampling should be conducted to verify the estimates. Entrelament estimates were subject to same problems as impingement. la sadition to the previously noted difficulties, entrainment estimates also present unique problems.

The specific problems reisted to entrainment may be summarized as follows:

a. Ichthyoplankton is apparently vertically stratified in the water column, being most abundant in the upper 1 to 2 meters. The portion (s) of the water column used by Cooper Nuclear Station was unknown and this could provide a source of error in the estimates,

b. The numbers of naturally morbid larvae could not be determined with certainty. This could provide another source of error in estimating the loss to adult fishery. Furthermore, it is not known what percent of the larvae is actually killed by the plant passage,

c. The fate of drif ting larvae in the Missouri River is presently enknown. If these larvae would naturally leave the system entrainment losses may not be significant. The reverse of this situation could also be true and entrainment could have serious long-term consequences. Complete pursuit of this last factor is beyond the scope of this present study.

d. It appegra that the Missouri River receives large numbers of fish larvae annually (estimated to be 400 to 500 million daily) from Cavins Point Dam and tributary streams. This large number of larvae does not seem to correlate with the small fisheries now practiced on the river.

C. DUANE ARNOLD ENERGY CENTER

1. Phytoplankton Phytoplankton collections were' taken twice per month _at five stations, using a Kemmerer or Van Dorn water sampler. This schedu.le was adequate to detect major chenges in river phytoplankton populations.- Based on .results of preoperational studies, low percentage of riverflow used by Duane Arnold Energy Center (DAEC),

62

results from the initial year of operational studies, and data from the IIterature relating to ' natural variability, continued sampling of phytoplankton was unnecessary. Separating station effects from natural changes would be extremely dif ficult, without the use of an impractically intense sampling program. The ef fort and cost required by such a program could not be justified by the information gained.

2. Periphyton Periphyton communities were studied using glass slides installed on boxes suspended in Cedar River upstream and downstream from DAEC.

The slides were left in the river for 2- to 4-week periods in  ;

spring, summer, and fall. Methods used seemed to be adequate.

Units used in reporting biomass were not consistent, which made comparisons between years difficult. Based on the small percentage of river flow used by DAEC, the small discharge plume, the results obtained, and the difficulty in separating station effects from natural changes without a massive sampling effort, it was not necessary to continue sampling periphyton af ter the first full year of station operation.

3. Zooplankton Zooplankton sampling was conducted as part of entrainment studies at DAEC. In 1974 and June 1975, collections were made using a Kensnerer sampler placed in front of the intake structure. Only 10 liters of water were collected and filtered through a plankton net. This method was inadequate co sample zooplankton, and beginning in July 1975, nets were used. Measurements of current velocity at the point where the nets were fish were used to calculate the volume of water filtered-for each sample. Single samples were collected three times yearly in 1974 and 1975, and four times yearly during 1976 through 1980.

Since zooplankton populations are normally found in a patchy distribution, it is important to control sampling variability which could mask actual population differences. The intake velocity depends on the depth of the river, which changes radically on a seasonal basis. Using towed nets in front of the intake would allow a standardized towing velocity and make samples comparable. Use of dif ferent tow speeds results in selection for different zooplankton organisms, depending on their net avoidance capabilities.

Standardizing tow speeds would elirinate this source of variability.

Taking 2 to 3 replicates during each sampling episode would assist in averaging out the normal patchiness.

Despite the shortcomings of the zoopinnkton sampling program, the same conclusions apply here as were stated for the phytoplankton 63

' program. No important information was gained by sampling beyond one year of plant operation.

4.. Benthic Macroinvertebrates Benthos samples were collected three or four times a year at two locations each upstream and downstream from DAEC, using a Ponar grab. The majority of the samples taken from 1974 through 1978 were devoid of macroinvertebrates. This paucity of specimens was attributed to the shifting, sandy substrate in the vicinity of the station. Collections from 1979 and 1980 yielded much greater numbers of organisms, apparently because samples were taken in areas with more silt and clay, as well as improved sorting and idantification techniques. Even 1979 and 1980 samples, with larger numbers than previous years, did not indicate a dense, diverse '

benthic community in the Cedar River near DAEC.

One year of quarterly sampling at the upstream and downstream stations, with at least two replicate Ponar grabs taken at each station, would be sufficient to confirm the preoperational predictions that only a small area (about 0.25 acre) of the river bottom near the discharge would be affected by station operation.

The small discharge plume and rapid mixing reinforce the probability of the station having no major effect on the benthos, liester-Dendy type artificial substrates were used to monitor Cedar River aquatic macroinvertebrates in 1977,1979, and 1980. The comments on the benthic macroinvertebrate progranc apply equally for artificial substrates.

5. Fish Fishery studies were conducted at sites upstream of and downstream from DAEC, using hoop nets, electroshocking units, and seines.

Samples were collected a nominal 3 times per year. The use of dif ferent gear types provided complementary species distributions, since each method is species-selective. Consistency was a problem throughout the operational years. The combination of gear types used changed from season to season and-year to year. Hoop nets were set for varyirg time periods; on occasion, they were set for a dif ferent number of days upstream and downstream from DAEC during the same sampling period. Electroshocking was carried out for pariods ranging from 10 to 90 minutes; on several occasions electroshocking was carried out for different. time periods upstream and downstream from DAEC during the same sampling period. No description of the seines used or the seining method was provided for 1974 to 1978. All these inconsistencies combined to make analyses and estimations of station-related effects difficult, at best.

p 64

c The combination of fishing gears used seemed to adequately sample the local fish populations. When stream flow or weather conditions prevented the use of a particular gear type, an effort should have been made to sample as soon as conditions allowed, rather ,than miss an entire season. Fish represent a high trophic level in the aquatic-system, and they are of most interest to man, when compared to other aquatic groups. They should be studied with a

~

comprehensive, consistent program, with the view that serious.

station-related effects on any level of the aquatic ecosystems will eventually be manifested in the higher level represented by fish.

6. Entrainment of Fish Eggs and Larvae Ichthyoplankton entrainment samples were collected three times yearly during 1974 and 1975, and four times yearly during 1976 through 1980. The same methods were used as were used for zooplankton collections in 1974 to 1978. In 1979 and 1980, samples were taken adjacent to the intake bar grill using a 0.5-m diameter, 571-micrometer mesh net. The net was fished for 5 to 10 minutes near the surface and near the bottom.

The same comments about patchiness in zooplankton apply to ichthyoplankton. In addition, fish larvae are of ten more abundant in the water column at night. Since the station uses water on a 24-hour basis, it is important to know the average number of fish larvae present in the water column at all times, not just during the day. It is also necessary to concentrate sampling efforts during spring and summer spawning periods. Only one or two of the single quarterly samples taken each year could be expected to catch any fish eggs or larvae.

Ichthyoplankton was not adequately sampled at DAEC. However, during the spawning season in spring and summer, Cedar River flows are usually at a yearly maximum, and the smallest yearly percentages of total flow are taken into the station. This would reduce the probability of entraining large numbers of fish eggs or larvae during the spawning season.

In addition, most fishes found in Cedar River have eggs and larvae which tend to remain near the bottom and would thus not be very susceptible to entrainment.

One year of intensive operational sampling for ichchyoplankton would probably confirm indications of previous results, that DAEC entrains extremely low numbers of fish eggs and larvae. If this confirmation occurred, it would not be necessary to continue the program.

65

s

7. L Impingement of Fish

~

Daily trash basket counts were made by DAEC personnel beginning .in January 1975. On four days each year, 24-hour trash basket counts leere made, during which all fish collected were identified as far

ss.possible,: weighed, and measured.

Data from impingement studies at DAEC and other stations indicate ihat t impingement is greatest during cold months, owhen fish are attracted to.the vicinity of the station by1the heated effluent.

Fish are particularly susceptible to impingement at DAEC during periods when warm water is released at the intake area to' prevent icing of the trash rack and screens.

DAEC does not impinge large numbers of fish. However, since the screens must be cleaned and the trash basket emptied on a regular schedule, it would require only a few extra minutes to count the fish in the basket before disposing of them. Monitoring impingement rates in this manner could be an extremely inexpensive method of obtaining useful data. If uncommonly large numbers of fish were impinged due to unusual circumstances, this simple

~

program would enable this fact to be recognized and any necessary

. mitigative measures to be taken. Fish are important to man, as well as to the aquatic ecosystem, and their rate of impingement should be monitored. The 24-hour trash basket counts should have been concentrated during the cold months. rather than spaced evenly throughout the. year, when it was determined that impingement was greatest during periods of cooler water temperatures.

8. Fish Cage Studies Studies nominally designed to examine effects of blowdown discharge~

from DAEC on native fish were conducted once each summer ' from 1974 to 1980. . Channel catfish (carpsuckers were used in 1977) were placed in each of three live boxes located immediately upstream of and downstream from DAEC and in the discharge canal. The fish were monitored for behavior changes and mortality for 48 to 51 hours5.902778e-4 days <br />0.0142 hours <br />8.43254e-5 weeks <br />1.94055e-5 months <br />.

Due to the use of inappropriate . fish species, the small number of

-individuals used, the low number of . experiments, 'and the inability to examine physical' factors independently of one another, theifish cage studies were not adequate - to permit an assessment of blowdown discharge effects on Cedar River fish..

During most of L the year, ~ fish in Cedar Xiver can avoid the blowdown Edischarge. .During-winter, fish can be physiologically restricted to the thermal plume, and thereby sub;ect to the effects of residual chlorine or its derivatives in. the discharge. ; Residual chlorine . in. the discharge plume should be measured on a regular basis,- during all combinations of riverflow and ' chlorination.

regimes. If chlorine -values are found, which, based on ' reporta .in m

66 4

the literature, are known to be potentially harmful to fish, .then mitigative measures should be taken. Particular attention should be given to winter chlorine levels.

9. Feetors Affecting Data Analyses-Evaluation of preoperational and operational aquatic ecological data for Cedar River near DAEC exposed a ' series of factors which complicated analyses. Sampling methodology and data reporting were often inconsistent between preoperational and operational studies, as well as from year to year during operational monitoring.

Sampling locations were changed from preoperational to operational studies for some parameters, prohibiting valid comparisons.

Some of the sampling problems seem to have been caused by extreme fluctuations' in Cedar River flow volumes. Changes in river flow were beyond the control of personnel doing the aquatic sampling, but, in many cases, it appeared that no effort was made to collect samples when the river returned to normal levels. Taking a sample a few weeks or a month late would still have provided useful information; completely bypassing a quarterly sampling effort leaves a large gap in the annual data.

As described previoualy, the combination of gear types used for sampling fish, as well as the period each gear type was deployed, were inconsistent from season to season and year to year.

Consistency in methodology is extremely important in order to permit valid comparisons and to discern station-related effects.

Sampling to estimate ichthyoplankton entrainment should have been concentrated during the known spawing season for Cedar River fishes.

' 67

PART V OVERVIEW This overview compares and contrasts the three nuclear generating stations, Fort Calhoun Station, Cooper Station, and DAEC, all of which are presently in commercial operation.

Two of these stations, Fort Calhoun Station and Cooper Station, have once-through condenser cooling systems, whereas DAEC employs a forced-draf t evaporative cooling tower. The first two stations, possessing different physical and operational characteristics (see Table V-1), are located within 100 river miles of each other and utilize the same cooling water source (the Missouri River). Comparisons and_ contrasts between these three stations are made to provide insights into the following:

(1) Dif ferences in magnitude of impacts associated with different maximum discharge temperatures and ZLTs; (2) Dif ferences in magnitude of impacts attributed to dif ferent cooling water intake volumes and intake velocities; (3) Potential impacts of cooling towers versus open-cycle systems; and (4) Effects of location and design of intake and discharge structures on stream biota of the Missouri River and Cedar River.

A. DISCHARGE TEMPERATURE AND lit The maximum discharge temperatures at Fort Calhoun Station, Cooper Station, and DAEC are 103, 103, and 90.5'F, respectively (see Table V-1). Both the For t Calhoun and Cooper Stations have a dLT range of 18 to 22*F, whereas DAEC has a lit range of 14 to 38*F. Despite dif ferences in both the maximum discharge temperature and ZiT between these stations, heated discharges from the three stations were not demonstrated to seriously impact primary producers (phytoplankton and periphyton), primary consumers (zooplankton), or higher trophic levels.

None of the three stations formed a thermal barrier across the width of the cooling water source nor interrupted fish movement or migration.

Localized effects on primary and secondary producers were observed.

These effects were minor and were restricted to the immediate discharge zone during the hot summer months. In contrast, no negative impacts were detected downstream of the stations' discharges, end a net stimulation of primary producers and consumers as well as some higher consumers (e.g., benthic macroinvertebrates) were measured downstream from the stations on the Missouri River during the remainder of the year.

It is anticipated that the discharge temperatures, ALT, and plume size of any of these three units will not impair or seriously impact any significant portion of the various biological parameters considered herein.

< 69

I Table V-1 Couperison of selected design, operating, asi fish inpact diaracteristics of Fort Calhoun Station, Cooper Nuclear Station, and Duane Arnold Energy Center Fort Calhotsi Cooper Maclear Duale Arnold Station Station Energy Center locaticn Washington County, Nebraska County, 1. inn County, Nebraska Nebraska Iowa Water Source Missouri River Missouri River Cedar River Date of First Ccanercial Power Generation September 1973 July 1974 May 1974 NetPower(40 475 778 569 Cooling System Once-throrgh Once-through Forced-draft coolirg towers Intake Design Shoreline intake Storeline is take Shoreline intake traveling screens traveling screens traveling screens Calculated IntakeVelocity(fps) 0.7-1.1 <2-2.5 @.3 Irtake Voltme (ne) 360,000 651,000 11.>00 Discharge Design Submerged tumel Canal Subnerged pipe Screen Mesh Sica (inch) 3/8 3/8 3/16 Discharge Velocity (fps) Not available Not available 6 Discharge voltme (gpa) 360,000 651,000 4,000 Percent River Water Used 1.3-4.9 0.94.5 <0.1-8.7 T (*F) Raige 18-22 18-22 14-38 11axinan Discharge Tecperature (*F) 103 103 90.5 Biofouling Control Now None Oilorine No. Fish Invinged/ Year 3 3 (estimated nean) 170 x 10 97 x 10 402 No. Fish Entrained / Year (estimated nean) 228 x 100 432 x 106 Very few EE8s and larvae Source: ESE,1981 4

70

B. INTAKE VOLUME AND INTAKE VELOCITY Both cooling water intake volume and intake velocity are related to the magnitude of entrainment of fish eggs and larvae, drif t/ floating organisms, and the impingement of juvenile and adult fish.

The dif ferences in cooling water intake volume between the three stations are substantial (see Table V-1). Due to inherent differences in the biota of the Cedar and the Missouri Rivers, it is difficult to directly compare DAEC with Fort Calhoun and Cooper Stations. For example, DAEC, with a cooling water intake volume of only 11,000 gpm, has negligible entrainment effect (few eggs and larvae) and impingement (402 fish / year) effects. This is attributed to a combination of comparatively small *ntake volume, very low intake velocity (0.3 fps),

and perhaps, a lower biological productivity of the Cedar River (Re f. 41) .

A comparison between Fort Calhoun and Cooper Stations indicates the following:

(1) Cooper Station generates a net of 778 MWe versus 475 MWe for Fort Calhoun Station.

(2) Cooper Station utilizes 1.8 times as much water as Fort Calhoun Station for cooling.

(3) The cooling water intake velocity at Cooper Station (<2 to 2.5 fps) is nearly 2.9 to 2.3 fps times faster than that of Fort Calhoun Station (0.7 to 1.1 fps) (i.e., Cooper Station operates at a much higher intake velocity than Fort Calhoun Station).

(4) The number of fish larvae estimated to be entrained at Cooper Station is nearly twice that found at Fort Calhoun Station (see Table V-1). Although these differences in entrainment may be attributed to a variety of factors, the large intake volume and the higher intake velocity at Cooper Station should account for a sizable portion of the larvae entrained.

(5) The number of fish impinged annually at Fort Calhoun Station is 1.8 times as great as the number impinged rt Cooper Station. Most of the fish impinged at both stations are. young-of-the-year.

Based on the differences in intake volume and intake velocity between the two stations, more fish should be impinged at Cooper Station than at. Fort Calhoun Station. This relatively large difference is due to:

(a) The presence of an intake structure guide wall at Cooper Station which apparently reduced impingement (but not entrainment).

(5) Fish population density near Cooper Station could have oeen less than fish density near Fort Calhoun Station.

71 i

a (c). Th'e methods used. in estimating (predicting) annua'l impingement rate at each station were .not compatible, and the collection methodology at each' station was different. -Hence, one could not utilize a single method of impingement calculation or estimation for both stations.

(d) The monthly, sample size at Cooper. Station varied from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />' per day at Fort Calhoun Station).

Sampling impinged fish for only 2, 4, or 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> monthly does not - provide reliable and consistent results (Ref. 42) .

C. INTAKE SCREEN MESH SIZE Fort Calhoun and Cooper Stations utilize vertical traveling screens with'3/8-inch square mesh. DAEC employs vertical traveling screens with 3/16-inch square mesh. Most of the fish impinged at each station were - young-o f-the year. Each station utilizes a screen mesh size that is appropriate to its operation as well as the cooling water. source.

For example, due to turbidity and the high silt load of the Missouri River, a mest. size smaller than 3/8-inch could prove restrictive or prohibitive due to screen clogging at Cooper and/or Fort Calhoun Stations.

D. INTAKE AND DISCHARGE DESIGN These three power generating stations ha re shoreline intake structures.

Their discharges consist of a submerged pip * (DAEC), submerged tunnel (Fort Calhoun Station, or open discharge canal (Cooper Station). In all three situations, the length and the orientation of the discharge structure (and, probably, the velocity of thel discharge) seem to preclude or minimize re-entrainment and enhance the cooling and mixing process with the receiving waters. The three stations have small mixing zones, and the plumes from Cooper and Fort Calhoun Stations and DAEC appear to " hug" the shoreline due to the hydrodynamic characteristics of the Missouri River in the f# rst two cases, and the Cedar River in the last case.

E. BI0 FOULING CONTROL The design of the three stations optimizes the utilization of the

. physical characteristics of the cooling -water - source. For example, biofouling inhibitors are not used at Fort Calhoun Station or at Cooper Station due to the high silt content of the Missouri River. The silt '

-scouring action minimizes the possibility of biofouling. -Chlorination has been used at DAEC.

F.

SUMMARY

AND CONCLUSION

. Major dif ferences 'in the impacts detected at the three stations on aquatic communities 'in the Missouri and Cedar ~ Rivers seen to be-attributed primarily to- differences in the cooling water intake volume, _

72

intake velocity, size of surface water system utilized and, most importantly, to the biological characteristics of tne affected water body system.

Despite the fact that the aquatic community of the Cedar River was not precisely quantified or defined (data were inconclusive in many cases),

entrainment and impingement data which were collected at the station indicate that this plant has ecologically sound characteristics. It uses a relatively small portion of the Cedar River for cooling purposts, and this segment of the river (the portion of the river affected by the plant's operation) can be termed biologically

" nonsensitive". These two factors (plant design and low biological productivity) are much desired during power plant siting.

Both Fort Calhoun and Cooper Stations entrained large numbers of fish larvae (and an unspecified number of fish eggs) and impinged large i numbers of fish. Although the removal of large numbers of fish and larvae was not reflected in the Missouri River commercial fisheries (based on available data), the location and design characteristics of these two stations may not be termed ecologically sound. As previously indicated, the hydrodynamic characteristics of the Missouri River tend to concentrate fish eggs and larvae near the Nebraska shoreline. The combined effects of station location and the large water volume (for Fort Calhoun and Cooper Stations) needed for cooling deserves a closer look at new stations prior to implementation.

Data collected at the three stations indicate that neither the maximum allowable temperature nor the measured 4LTs were shown to have adversely impacted the biota in the receiving waters.

1 1 73

PART VI RECOMMENDATIONS A. PREOPERATIONAL NONRADIOLOGICAL MONITORING STUDIES Based on evaluations presented herein on the three nuclear power stations, Fort Calhoun Station, Cooper Station, and DAEC, and assuming that similar units were to be located on similar water body systems of the same geographical area, it is recommended that the following be considered and implemented in the design of future preoperational-phase environmental monitoring programs:

(1) Baseline studies should be designed with consideration of avail-able, site-specific historical data and life history information of species known to occur commonly within the project area. This information should assist in locating sampling stations and in determining the sampling methodology, period and frequency of sampling, and the number of sample replicates. The relative bio-logical values cf dif ferent water body segments within the proposed ecosystem, indigenous and nonindigenous species, habitats of Representative Important Species, and critical time of the year for life history aspects of each species can be determined.

(2) Baseline resource utilization must be properly defined. Efforts should be made to access and maintain recreational and, if applicable, commercial fisheries data for the project area.

Annual (or seasonal) creel censuses should be conducted if such data are not otherwise available.

(3) Initially, unless a satisfactory, existing data base is readily available, all trophic levels should be monitored and evaluated.

Emphasis should be placed on fish, fish e8Fs, and larvae. The monitoring effort should be adequate to include areas of predicted impacts. It should continue for a minimum of two years for benthic macroinvertebrates, fish eggs and larvae, and juvenile and adult fish. The reasons for this monitoring duration are:

a. To account for between years variability (e.g. , strong- versus poor year classes),

b. Adjust for sampling years,

c. Fine tune field and laboratory techniques (the literature is repicte with examples of requirements for modification /

improvement during the monitoring effort).

Lower trophic levels (phytoplankton, periphyton, zooplankton) should be monitored for a minimum of one year, especially should conditions at the proposed site be considered different from areas upstream (or downstream) from the proposed site. Land use patterns (e.g., agriculture), tributary streams, impoundments and industrial outfalls (other than heated discharges) at or near the proposed site could rapidly sad dramatically change the structure er.ia the behavior of these lower trophic-level communities 75 L l

(generation time for phytoplankton is a few hours and generation time for zooplankton is a few days). These conditions could dictrte the need for site-specific data. Baseline studies should yield some measures of the productivity of the system. These measures could be used as ind ice s , thus allowing operational impacts to be measured in a concise fashion. For example, after determining the primary productivity of phytoplankton during the baseline evaluation phase, monitoring that primary productivity index early in the operational phase could be used as an impact indicator, thus m Simizing extensive operational sampling efforts.

(4) To the maximum extent possible, the sample collection gear should be quantitative (i.e. , providing "per-unit volume", "per-unit area" data). Every effort should be made to ensure consistency in the sampling methodology and the location of stations for repetitive sampling. Vertical as well as horizontal distributions of aquatic communities should be determined.

(5) Estimates on fish eggs and larval mortality attributed to sampling gear should be sought after at the baseline level when possible collection techniques for fish eggs and larvae should allow for sampling at an intake velocity comparable to that anticipated for the plant, when feasible.

B. OPERATIONAL NONRADIOLOGICAL MONITORING STUDIES It is recommended that the following be considered and implemented in the design of future operational phase environmentM monitoring programs:

(1) Under conditions comparable to those within the scope of this document, it is recommended that phytoplankton, neriphyton, and zooplankton (except any zooplankter defined as a Representative Important Species) not be monitored during the operational phase.

This would require that previous studies by similar power generating stations utilizing the same or a very similar water drainage system have statistically demonstreted the lack of any significant impact on these trophic levels as a result of power generation. The proposed location of the new station should be at s distance far enough from the nearest existing station and the river flow rate should be such that these three low trophic levels would be allowed enough time to regenerate since their populations would become partially entrained at the proposed or the existing station. Results of laseline studies associated with the proposed generating unit should demonstrate the area described as the least sensitive or biologically least productive regarding station location.

(a) In those project areas having surface water resources, bio-logical communities, and generating station characteristics comparable to those within the scope of this document , it is 76

recommer.ded that, in the absence of conditions stated pre-viously, phytoplankton, periphyton and zooplankton (except zooplankters classified as Representative Important Species) only be " cross checke'd" after one year if normal , design-load operation is achieved. This checking and re-evaluation process should be conducted seasonally for four successive seasons for a maximum of one year. This re-evaluation process should be based on a simple but sound program (e.g. ,

cross checking phytoplankton productivity [index] would be .,

sufficient). Should no significant impacts to these l biological connunities be indicated, further studies of phytoplankton, periphyton, and zooplankton should be subject to elimination or a greatly reduced level of effort.

Operational phase monitoring of higher trophic levels should be used as the basis to detect any significant impact or catastrophic changes in lower trophic levels. Examples would be fish feeding behavior and the " health" of fish and macroinvertebrate communities.

(b) For all biological parameters, it is emphasized that the sample collection gear, frequency, and stations must be compatible with those employed in the preoperational baseline monitoring program.

(c) Impingement, entrainment, and river fish population studies should continue with the operational-phase for a minimum of five years (as presently specified in ETSs). This 5-year period should occur when plant operations are stabilized, after the period of initial plant start-up and load testing.

(d) Should station design and conditions allow, entrainment collections should be taken inside intake structures and plumes in addition to control stations within the cooling water resource.

(e) Impingement and entrainment sampling efforts should be intensified during periods of spawning activity and seasonal arrival of young-of-the year, juvenile and adult fish.

Uniform sampling efforts can result in inadequate sampling when " target species" are most abundant. Additionally, over-sampling when species are known to be scarce or absent yields no substantive information.

( f) Impingement collection episodes should be taken at 2- to 4-hour intervals over a 24-hour period. There should be a distinctive log entry between collections taken within day-light and darkness.

C. INTEGRATED IMPACT ASSESSMENTS In those circumstances where more than 'one: high-volume user is with-drawing water from the same surface water resource, it is strongly reaommended that consideration be given to -an " integrated impacts" or combined-ef fects approach.

77 g - , -

Results presented within this document indicate that significant impacts associated with plant intakes (at the Fort Calhoun Station, for example) were not identified. Ten cooling-water intakes are located between Fort Calhoun Station and the Mississippi River. Had one been able to address the combined, syners,istic effects of the entrainment of all these intakes on the blota of the Missouri River, conclusions ralative to impacts would be more circumspect and prudent and, possibly, different.

The analyses presented in this document indicated that Fort Calhoun Station removed on estinated total of 2,960,000 fish larvae daily (and an undetermined number of eggs). The remaining larval fish population which passed the station would also be subjected to entrainment at Cooper Station (117 river miles downstream) within 1 to 2 days (average riverflow is 5 fps) . While an estimated 22% of all river larval input (Ref. 39) occurs between the two stations, larger fish larvae (10 to 12 mm in length) may enter protected areas. However, larval fish passing Fort Calhoun Station will suffer some losses at Cooper Station, and this process could be repeated downstream from Cooper Station. Due to the relatively fast flow of the Missouri River, drif ting fish eggs and larvae may not have adequate time to become motile should consecutive cooling water intakes become closely spaced.

Working on fish larval drif t in the Missouri River, Harrow and Schlesinger (Ref. 39) reported a dramatic decline in the number of drift larvae once they become approximately 8 to 12 m in length. They attributed this decline to either a catastrophic die-off or the entry of these fish into protected habitat. Larvae less than 8 m in length would, th e re fore , be subject to successive entrainment potential.

Unless larvae are given time to grow (and leave the entraineble larval fish population) or entrained larvae are replaced by additional recruitment into the river, a cumulative ef fect on fish populations may be seen downstream due to cumulative entrainma.tt impacts upstream.

Studies on total larval input into the Missouri River (Ref. 39) between Gavins Point Dam, Nebraska and Leavenworth, Kansas, indicated that of the total larval fish input to the river, 63.3% and 22% are introduced to the river above Fort Calhoun Station and above Cooper Station, respectively. Given that there are ten cooling water intakes on the Missouri River below Fort Calhoun Station and that only 12.7% of the total larval input is introduced into the river below Cooper Stacion, it remains to be determined whether this recruitment is adequate to compensate for larval fish losses at those intakes. Furthermore, larger larvae which may have become separated from the drif t comunity are not protected from impingement at these downstream sites. Such larvae remain vulnerable to impingement until they reach at least 100 m in length.

The removal of fish eggs, larvae, and young-of-the year from the potential population at either Fort Calhoun Station and/or Cooper Station may not be severe as isolated impacts. However, the 78

cumulative impacts of ten intake structures may have additive effects.

Consequently, a different conclusion could be reached unless those animals removed at ~ successive stations are eff2ctively replaced by additional input s or other compensatory factors which are not now evident.

D. INTAKE / DISCHARGE DESIGN AND LOCATION The following paragraphs provide recommendations on conitoring programs and sampling. criteria associated with intake and discharge design and location. Some of these recommendations parallel the guidance provided by the U.S. Environmental Protection Agency (EPA) (Refs. 82, 43, and

44) and the U.S. Fish and Wildlife Service (Ref. 29). Others are based on the analyses presented throughout this document as well as experi-ence gained during studies on a variety of other power generating units.

l The objectives of these monitoring efforts should provide, as a j minimum, insights into the following aspects of potentially impacted '

important fish and macroinvertebrate populations:

(1) Locations of spawning grounds. i (2) Locations of nursery grounds.

(3) Locations of migratory routes (upstream / downstream movement).

(4) Areas of young-of-the year and adult concentrations.

(5) Location and size of sports and commercial fisheries.

(6) Existing stresses and/or pollution sources.

(7) Dynamic aspects of important (economically valuable) species.

The following major 1spects should be incorporated into the design of the monitoring program:

(1) Capability of the program to be used in assessing potential interaction of eges. Larvae, young-of-the year, and adults with the intake struerure.

(2) Accumulation of an adequate data base for all important species at the site. For example, the food habits, growth pattern, and reproductive behaviors of sports and commercial species from the af fected water body should be evaluated.

(3) Maximum use of existing data to determine larval mortality estimates in the presence and absence of the power station.

s4) Sampling intensively at the time of peak activity and density of young-of-the-year during spring and summer seasons.

(5) Sampling during peak activicy, especially in that segment of the river where an intake may actually be placed, making impingement and entrainment impact assessment more feasible.

(6) Correlation of preliminary findings on eggs, larvae, juveniles, and adults (concentration, movement, habitats, utilization, etc.), with available literature.

Field programs should be designed af ter a thorough review of locations and evaluating the status of commercial and sports fisheries in the region.

79

The design of the sampling program should be closely tied to the size and the design of the plant itself. For example, based on the three power plants evaluated in this document, both Fort Calhoun and Cooper Stations have once-through cooling systems with relatively large cooling water intake volumes and high intake velocities. While closed-cycle systems ace not considered the best technology available, in these situations, closed-cycle systems probably would have been more environmentally sound. The U.S. EPA gridance manual (Ref. 28) for evaluating the adverse impacts of cooling water intake specifically states:

" Reducing cooling water flow is generally an effective means for minimizing potential entrainment impact. In fact, this may be the only feasible means to reduce impact of entrainment where potentially involved organisms are in relatively large concentration and uni formly distributed in the water column.

Entrapment and impingement may also be lessened with lower flow as proportionally fewer animals will be subject to contact with the intake structure; water velacities associated with the structure can be reduced, enhancing probability of survival if impinged or of escape if trapped."

The manual further states:

" Generally, the combination of low (biological) value and low flow most likely is a reflection of best technology available in location, design and operation of the intake structure.

Exceptions to this could involve significantly affected rare and endangered species."

Field programs should be guided by previous scientific efforts, published and unpublished. In those cases where there exists a satisfactory data base, duplication of efforts should be avoided.

However, updating verification and validation of previous data is a focal point.

A combination of fish collection techniques should be utilized. These techniques may include trammel nets, surface trawls, bottom trawls, surface gill nets, bottom gill nets, and el ectroshockers. Sampling gear should be selected on the basis of habitat, mech size, time of collection, setting or trawling duration, etc.

Stations should be placed in areas of potential intake or discharge locations, least ecologically sensitive areas, and biologically productive areas in order to provide a complete representation of the water body.

Sampling programs must be characterized by having an adequate number of stations placed within each applicable water body. These stations 80

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. shoul'd.be selected to: (a) represent different habitats; (b) locate migratory routes;.and (c) locate' areas of species concentrations.

Important food resources for- desired species should be emphasized.

g ' Adequate data' on food and feeding,: reproduction, movement, and growth should be collected.

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PART VII REFERENCES

1. U.S. Atomic Energy Commission. 1972. Final Environmental Statement Related to Operation of Fort Calhoun Statiou, Unit 1, Omaha Public Power

t. strict, Docket No. 50-285.

2. Harrow, L., King, R., Bliss, G., and Kline, P. 1977. The Effects of Entrainment and Impingement at the Fort Calhoun Station on the Fisheries of the Channelized Missouri River. Environmental Series Bulletin No. 3, Omaha Public Power District, Omaha, Nebraska, 114 pages.

3. Nebraska Public Power District. 1977. Annual Environmental Operating Report, Volume I--Nonradiological, January 1, 1977 to December 31, 1977, Cooper Nuclear Station. NRC Docket No. 50-298, DPR-46,

4. Nebraska Public Power District. 1973. Final Environmental Statement Related to Operation of Cooper Nuclear Station. Docket No. 50-298, l'qited States Atomic Energy Commission (NRC), Directorate of Licensing.

5. Industrial BIO-Test Laboratories, Inc. 1975a. The Evaluation of Thermal Effects in the Missouri River Near Cooper Nuclear Station (Preoperational Phase), April 1973 to March 1974. (IBT No. 64303322).

Report to Nebraska Public Power District, Columbus, Nebraska. 252 pages and 8 appendices.

6. Industrial BIO-Test Laboratories, Inc. 1975b. The Evaluation of Thermal Effects in the Missouri River Near Cooper Nuclear Station (Operational Phase), January to December 1974. (IBT No. 64304909).

Report to Nebraska Public Power District, Columbus, Nebraska. 262 pages and 9 appendices.

7. NALCO Environmental Sciences. 1976. The Evaluation of Thermal Effects in the Missouri River Near Cooper Nuclear Station (Operational Phase),

January to December 1975. (Project No. 5501-06419). Report to Nebraska Public Power District, Columbus, Nebraska. 261 pages and 9 appendices.

8. NALCO F.nvironmental Sciences. 1977. The Evaluation of Thermal Ef fects in the Missouri River Near Cooper Nuclear Station (Operational Phase),

January to December 1976. (Project No. 5501-07666). Report to Nebraska Public Power District, Columbus, Nebraska. 245 pages and 9 appendices.

9. NALCO Environmental Sciences. 1978. The Evaluation of Thermal Ef fects in the Missouri River Near Cooper Nuclear Statien (Operational Phase),

January to December 1977. Report to Nebraska Public Power District, Columbus, Nebraska. 265 pages and 9 appendices.

T 83

- . . . g

10. Hazleton Environmental Sciences. 1979. The Evaluation 6f Thermal Effects in the Missouri River Near Cooper Nuclear Station (Operational Phase), January to December 1978. Report to Nebraska Public Power District, Columbus, Nebraska. 222 pages and 8 appendices.

11. Hesse, L.W. and Wallace, C.R. 1976. The Ef fects of Cooling Water Discharges from Fort Calhoun and Cooper Nuclear Stations on the Fishes of the Missouri River. Nebraska Game and Parks Commission, Lincoln, Nebraska. 377 pages.

12. Cada, C.F. 1977. The Entrainment of Larval Fishes at Two Nuclear Power Plants on the Missouri River in Nebraska. Doctoral Dissertation.

University of Nebraska, Lincoln, Nebraska.

13. Rogers, G.D. 1977. Entrainment of Crustacean Zooplankton Through Fort Calhoun Station. In: L.D. Jensen, ed. Fourth National Workshop on Entrainment and Impingement. Ecological Analysts, Inc. Melville, New York.

14. U.S. Atomic Energy Commission. 1973. Final Environmental Statement Related to Operation of Duane Arnold Energy Center. Docket No. 50-331.

United States Atomic Energy Commission (NRC), Directorate of Licensing.

15. Iowa Electric Light and Power Company. 1975. Semi-annual Operating Report. July 1, 1974 to December 31, 1974. Duane Arnold Energy Center, Unit I. NRC Docket No. 50-331.

16. Iowa Electric Light and Power Company. 1980. Duane Arnold Energy Center, Cedar River Operational Ecological Study. January through December 1979. NRC Docket No. 50-331.

17. Iowa Electric Light and Power Company. 1976. Semi-annual Operating Report. July 1, 1975 to December 31, 1975. Duane Arnold Energy Center, Unit !. NRC Docket No. 50-331.

18. Iowa Electric Light and Power Company. 1977. Duane Arnold Energy Center Operational Ecological Study: Annual Report. January 1976 to December 1976. NRC Docket No. 50-331.

19. Iowa Electric Light and Power Company. 1978. Duane Arnold Energy Center, Cedar River Operational Ecological Study: Annual Report.

January 1977 to December 1977. NRC Docket No. 50-331.

20. Iowa Electric Light and Power Company. 1979. Duane Arnold Energy Center, Cedar River Operational Ecological Study: Annual Report.

January 1978 to December 1978. NRC Docket No. 50-331,

21. Iowa Electric Light and Power Company. 1981. Operational Ecological Study in the Cedar River near Duane Arnold Energy Center. January thiough December 1980. NRC Docket No. 50-331.

T 84

22. Cada, G.F. 1977. The Entrainment of Larval Fishes at Two Nuclear Power Plants on the Missouri River in Nebraska. Doctoral Dissertation.

University of Nebraska, Lincoln, Nebraska.

23. Environmental Science and Engineering, Inc. 1981. Fort Calhoun Station, Unit 1, Final Environmental Appraisal Report. (NUREG/CR-2337, Vol.1)

24. Schainost, S. 1976. Survey of 1976 Commercial Fisheries Industry of Nebraska. Nebraska Game and Parks Commission, Fisheries Division, Lincoln, Nebraska. 32 pages.

25. U.S. Fnvironmental Protection Agency. 1973. Reviewing Environmental Impact Statements - Power Plant Cooling Systems, Engineering Aspects.

Environmental Protection Technology Series EPA-660/2-73-016. Corvallis, Oregon. 93 pp.

26. U.S. Nuclear Regulatory Commission. 1975. Regulatory Guide 4.7.

General Site Duitability Criteria for Nuclear Power Stations.

Washington, D.C. 30 pp.

27. U.S. Fish and Wildlife Service. 1974. Navigable Waters Handbook.

Loose-Leaf pub. n.p.

28. U.S. Environmental Protection Agency. 1977. Guidance for Evaluating the Adverse Impact of Cooling Water Intake Structures on the Aquatic Environment: Section 316(b), P.L.92-500. U.S. EPA, Of fice of Wuter Enforcement, Permits Division. Industrial Permits Branch.

Washington, D.C.

29. U.S. Fish and Wildlife Service. 1977. Impacts of Power Plant Intake Velocities on Fish. U.S. Department of the Interior. FWS/0BS-76/20.1.

30. Harrell, L. , Van Eppsand, T. , and Hatcher , R.1975. Progress Report for a 316(b) Study on the Robert A. Gallagher Power Plant. Dames and Moore, Cincinnati, Ohio. 43 pages.

31. Schainost, S. 1977. Survey of 1976 Commercial Fisheries Industry of Nebraska. Nebraska Game and Parks Commission, Fisheries Division, Lincoln, Nebraska. 32 pages.

32. Nebraska Game and Parks Ccmmission. 1979. State Comprehensive Outdoor Recreation Plan (SCORP). 186 pages and appendices.

33. U.S. Army Corps of Engineers. 1981. Missouri River Bank Stabilization and Navigation Project Draft Feasibility Report and Draft EIS for the Fish and Wildlife Mitigatir n Plan. 53 pages and appendices.

85

34. Boreman, J. 1977. Impacts of Power Plant Intake Velocities on Fish.

Biological Services Program FWS/0BS-76/20.1 Topical Briefs: Fish and Wildlife Resources and Electric Power Generation, No. 1. 9 pages.

35. NALCO Environmental Sciences. 1977. Operational Environmental Monitoring in the Missouri River Near Fort Calhoun Station, October 1973 through June 1977. A Survey Report to OPPD. 85 pages.

36. Weber, C.I. 1973. Biological Field and Laboratory Methods for Measuring the Quality of Surface Waters and Effluents.

EPA-67014-73-001. Of fice of Research and Development, U.S. EPA, Cincinnati, Ohio.

37. U.S. Fish and Wildlife Service. 1978. Factors Associated with Accuracy in Sampling Fish Eggs and Larvae. U.S. Department of the Interior, Biological Services Program, FWS/0BS-78-83.

38. U.S. Nuclear Regulatory Commission. 1978. Final Environmental Statement Related to the Determinction of the Suitability of the Site for Eventual Construction of the Fort Calhoun Station, Unit No. 2.

Omaha Public Power District.

39. Harrow, L.G., and Schlesinger, A.B. 1980. The Larval Fish Recruitment Study. Omaha Public Power District, Omaha, Nebraska. 92 pages.

40. Merriman, D., and Thorpe, L. 1976. The Connecticut River Ecological Study. The Impact of a Nuclear Power Plant. Monograoh No. 1 American Fisheries Society, Washington, D.C. 252 pages.

41. Environmental Science and Engineering, Inc. 1981. Duane Arnold Energy Center, Final Environmental Appraisal Report. (NUREG/CR-2337, Vol. 3)

42. Environmental Science and Engineering, Inc. 1981. Cooper Nuclear Station, Final Environnental Appraisal Report. (NUREG/CR-2337, Vol. 2)

43. U.S. . Environmental Protection Agency. 1974 316(a) Technical Guidance:

Thermal Discharges. U.S. EPA Water Planning Division. Office of Water and Hazardous Materials, Washington, D.C.

44. U.S. Environmental Protection Agency. 1976. Development Document for Best Technology Available for the Location, Design, Construction and Capacity of Cooling Water Intake Structures for Minimizing Adverse Environmental Impact. U.S. EPA, Washington, D.C. EPA 440/1-761015-a, 263 pages.

86

,y U.S. NUCLE AR REGUL ATORY COMMISilON BIBLIOGRAPHIC DATA SHEET NUREG/CR-2337, Vol. 4 4 TITLE AND SU8TtTLE LAdd Vooume No, of apprmriere) 2. fleeve ble'hl Aquatic Impacts from Operation of Three Midwestern Nuclear Power Stations 3 gge,pigg7.S ACCESSION NO.

Comparative Summary and Recommendatians for Nuclear l Station Sitinc and Desien 7, AUTHOR tSt 5. DATE REPORT COMPLE TED MONTH l YEAR Farouh El-Shamy, Stephen Berkowitz, James Brice August 1981

9. PE RF ORMING ORGANIZATION NAME AND MAILING ADORE SS (include IW Codel DATE REPORT ISSUED uoNTH Environmental Science and Engineering, Inc. lVEAR October 1981 P.O. Box ESE 6 (teeve <sa*>

Gainesville, Florida 32601

8. (Leave blenhi

12. SPONSORING ORGANIZ ATION NAME AND MAILING ADDRESS (inctuoe tw Codel ,

Division of Engineering Office of Nuclear Reactor Regulation t i. cONTR ACT NO.

=

U.S. Nuclear Regulatory Commission Washington, DC 20555 FIN B6854 13 TYPE OF REPORT PE RioD Cove RE D (Inclusive dares/

15 SUPPLEMENTARY NOTES 14 (Leave dis' A J 16 ABSTR ACT (200 swords or less/

Ecological impacts of three midwestern nuclear stations on riverine ecosystems were assessed. Station location, intake apr: discharge location and design were evaluated as to their interaction with dif ferent tu 7 hic levels. Fort Calhoun and Cooper Stations, located in Nebraska, utilize once-through cooling systems: these stations' cooling waters are withdrawn from and returned to the Missouri Riwr. Duane Arnold Energy Center located in Iowa, has a forced-draf t cooling tower and the station withdraws make-up water from the Cedar River.

Based,on the assessment of three particular stations, it was concluded that cooling towers are more environmentally sound than once-through ' cooling systems util! zing large volumes of cooling water. Recominendations were made that ef forts used for assessing impacts on lower trophic levels of current and future stations, be reduced or eliminated based on a case-by-case evaluation. Conversely, the current design and execution of fish and ichthyoplankton programs deserve a closer look. These trophi. levels call ft r the g expenditure of more effort during baseline and operat ional phase monitoring programs.

t 7 KE Y WORDS AND DOCUMENT AN ALYSIS 17a DE SCRIPTC885 nuclear generating station, environmental appraisal, impingement, entrainment ,

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