ML19341A367

Final Rept, Ecological Monitoring Fort St Vrain Generating Station for 1972-79.

ML19341A367
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/26/1980
From:	Glover F, Johns J, Schleiger T PUBLIC SERVICE CO. OF COLORADO, THORNE ECOLOGICAL INSTITUTE
To:
References
NUDOCS 8101230187
Download: ML19341A367 (220)

Text

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l I FORTST.VRAINNUCLEARGENkRATINGSTATION ECOLOGICAL MONITORING PROGRAM l

I Final Report covering the period 1972 - 1979 Prepared by:/s/ '"

N- k" p 7 F. Fred A. Glover, Project Director, Thorne Date i

Ecological Institute Reviewed by:/

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Reviewed by:/s/ ( u 72680 N

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""iL"nty:isi 2,As:. f ca W absNo Nplear Project Department ' ' Date' l

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Final Report l

l covering the period 3 1972 - 1979 ECOLOGICAL MONITOR'ING FORT ST. VPAIN NUCLEAR GENERATING STATION for l

Public Service Company O of Colorado O

by Thorne Ecological Institute 3 4860 P.tverbend Road Bealder, Colorado b

Dr. Fred A. Glover Project Director D

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TABLE OF CONTENTS

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S uma ry . . . . . . . .......................

7 Introduction ............................

Investigator Reports ........................ 9 Aquatic Section ........................ 10

) Invertebrates . . . . . . . . . . . . . . . . . . . . . . . 11 Algae . . . . . . . . . . ................. 75 Avian Sec'. ion ........... ............. 99 l

Terrestr'al Section . . . . . . . . . . . . . . . . . . . . . 116

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Vege '.ati on . . . . . . . . . . . . . . . . . . . . . . . 117 Ecophysiological Characteristics ...... . . . . . 138 Mammals, Amphibians and Reptiles . . . . . . . . . . . . 16 3 j

I nv e rte b rat e s . . . . . . . . . . . . . . . . . . . . . . 191 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . 215

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SUMMARY

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General Sumary This final report presents non-radiation, environmental data covering the general period 1972-1979. For the most part, the Fort St. Vrain envi-rons have maintained comparable quality over the years monitored, with local area and environmental component independent, natural variations.

All environmental components have experienced difficulty in determining cause and effect relationships because of the intermittent, irregular, and limited operation of the Nuclear Generating Station. O Based on the information available, no discernible, harmful effects on the biological environment are evident.

O Aquatic Section Invertebrates The macroinvertebrate community is composed of taxa tolerant of ,

moderate pollution. The various collection stations had similar faunas each season each year. Eight orders of insects and six non-insect inver-tebrate groups were collected with Diptera and Oligochaeta dominating.

O Chironomidae were the most abundant in numbers and taxa. Analysis of the chemical parameters of the aquatic environments did not reveal any abnormal or unexpected conditions. Because of data vagaries, analysis 9

of water temperature regimes possibly created by Generating Station operation and the effects on the macroinvertebrate aquatic community was inconclusive.

O Fish Collections have been made in both the St. Vrain and South Platte Rivers over the years. Species composition has remained about the same. O O

) 3 Most of the species are regarded as being pollution tolerant. Fish foods

$ have varied but in the main the items taken (numbers, kinds, and volume) have reflected relative availability of the organisms.

g Algae l

There has been a general similarity in species composition and l

numbers with variations seasonally and by sites, while species diversity i

j has remained consistently low in all aquatic habitats. The algae present j indicate polluted conditions and apparently no direct effects from the j Generating Station.

I 3 Avian Section Regular censuses were conducted from 1972-1979 of the birds utilizing the Generating Station area. During this census period avian populations 3 fluctuated widely and no specific trend was apparent. A seasonal pattern was evident with species present usually highest in May. Avian diversity has remained rather constant. Environmental impacts other than the 3 Nuclear Generating Station have had the greatest effects upon the birds.

Terrestrial Section Vegetation Data obtained from pennanent exclosures have indicated an increase in production values as a result of release from grazing pressure.

However, the native perennial grasses apparently have not had sufficient

.3 time to increase. To date, the Nuclear Generating Station has had little l or no apparent influence on the vegetation comunities of the area. It is believed that Station operational consistency over a longer period 3 of time will L needed to evaluate probable effects on vegetation.

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4 C' Ecophysiological Characteristics In general, leaf area injured decreased with time during the growing seasons for most years of study. Elemental concentrations in semples of kochia and cottonwood were influenced little by distance or direction from the Generating Station. Five chemical constituents (P, Ca, Zn, Fe, '

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-S) in pinto bean plants from the controlled experiment increased in concentration after Station startup. Heavy metals (Hg, Pg, and Cd) did not change with Station startup.

• Mammals, Amphibians and Reptiles Mammalian species composition has been similar over the survey years, ,

except that the thirteen-lined and spotted ground squirrels have not been observed recently. Deer mice and house mice are the most common specias and their numbers appear to have stabilized. The other mamals have shown greater fluctuation. Amphibians and reptiles have remained about the same in response to temperature and moisture conditions. Few seasonal or yearly differences occurred in heavy metal (Pb, Zn, and Cu) concentra-O tions in Microtus tissues. In amphibians the heavy metal situation was affected by local water conditions. Changes in numbers and species of mamals, amphibians and reptiles cannot be related to Station operation, O

but rather, seem to be influenced by agricultural activities.

Terrestrial Invertebrates Collembola, Formicidae, Silpha ramosa, and Araneida were used as e biological indicators of stress conditions from operation of the Nuclear Generating Station. Collembola distribution was generally unifom but population levels varied considerably. Formicidae populations were g O

5 similar from three sample areas. Both Collembola and Formicidae

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experienced variations, which were regarded as natural fluctuations.

Silpha ramosa populations are related to the availability of small mamal carcasses. Over the survey period there were population decreases

) and recoveries; all regarded as typical, natural variations. The general populations of Araneida are declining in the vicinity of the Station but the cause is not known.

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6 1, Fort St. Vrain Generation Summary O

Dates with Number of Gross Electric Days Without Generation Year and Month Generation Generatio1 MWH 1976 g December 11-31 10 23,842 1977 January 1-30 1 49,580 February 0 28 0 9 March 31 30 587 April 2-8 23 8,333 May 8-12, 14, 16-22 18 13,743 June 0 30 0 July 22, 23 29 1,150 August 6, 8-13, 17-18, 20-24 17 15,468 9 September 4-8, 12-30 6 46,519 October 1-25, 27-31 1 79,146 November 13-17, 20-30 14 46,509 December 0 31 0 1978 January 13-23 20 34,290 February 0 28 0 March 0 31 0 April 4-19, 21-30 4 65,850 May 1-8, 10-26, 28-31 2 99,073 e June 1-6, 12-29 6 98,459 July 3-14, 17-31 5 85,839 August 18, 19, 21-31 18 14,496 September 1-8 23 25,147 October 5-12, 14-17, 31 18 24,880 November 1-29 1 110,594 g December 9-31 8 92,583 1979 January 1-19, 23-31 3 109,306 ,

February

• 1 27 546 ,l March

• 0 31 0 l April

• 0 30 0 May* 0 31 0 June

• O 30 0 July

• 23, 26-28, 30, 31 25 4,522 August 3-17, 20-24, 26-31 5 88,079 ,.

September 1 29 1,828 -

October 2-14, 24-26 15 46,367 November 0 30 0 December 0 31 0

• Refueling outage February 1 - July 22,1979. ,

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Introduction O

This final report presents summarized, non-radiological, environ-mental monitoring information concerned with the period 1972-1979.

Baseline environmental studies were conducted at the Fort St. Vrain site O

in 1971 and a pre-NEPA environmental report was prepared. Additional background information on soils, vegetation taxonomy, water chemistry, and hydrology was obtained about the environs of the Nuclear Generating O

Station and reported upon (Glover,1976), which provided a biological benchmark for the initiation of the Station monitoring program.

Throughout the period covered by this report there have been only O

minor changes in personnel. The Thorne Ecological Institute has been the sole contractor involved. Each investigator has operated on an individual field schedule and program. However, there are many instances of interdisciplinary, coordinated, cooperative efforts. The Thorne team has met with Public Service Company representatives as needed for reporting, interaction, coordination, discussions about progress, and the resolving of operational problems.

• The intennittent, irregular, and liWed operation of the Nuclear Generating Station has made it difficult or impossible to develop usable cause and effect data. Based on the information available, no discernible, O harmful effects on the biological environment are evident to date.

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INVESTIGATOR REPORTS 3

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Oi AQUATIC SECTION e

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J AQUATIC It4 VERTEBRATE MONITORING D

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by Clarence A. Carlson 0 and David L. Propst O

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12 INTRODUCTION e

Routine monitoring of the aquatic fauna of the South Platte and St. Vrain Rivers in the vicinity of the Fort St. Vrain Nuclear Generating Station, Colorado, began on a regular basis in May 1974. Baseline studies e on the aquatic fauna were initiated in 1971 and continued intermittently through 1973. The baseline data were presented in several reports, theses and publications (Galat and McConnell 1974; Eder, Carlson and Fronk 1974; e Carlson 1976a, Carlson 1976b; Johnson 1972; Eder 1974; and Eder and Carlson 1977). An environmental impact analysis was completed for the Public Service Company of Colorado in 1971. e:

Biweekly macroinvertebrate and annual fish collections were made to determine if the effluent discharged into the South Platte River by the Fort St. Vrain Nuclear Generating Station would have a discernible effect g upon the resident macroinvertebrate and/or fish communities. Detection of changes depended upon the resolution ability of the techniques employed.

Confounding analysis of possible effects of Station effluent was the ,

import of various organic and inorganic pollutants from upstream.

Near the Station, the South Platte River (and the St. Vrain River to a lesser extent) is tremendously modified from its natural, historical ,

condition. Industrial and municipal wastes are discharged into the river at a number of points. Runoff from agricultural lands exacerbates the enrichment of the system. Dams and irrigation withdrawal and return ,

reduce the amplituc'e of natural seasonal and diurnal flow fluctuations.

Diminution of spring runoff reduces the flushing capability of the stream.

Highe'c than natural sumer flows expand available habitat for aquatic e1 fauna.

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) 13 Near the Station, both streams have been characterized as being in

) a recovery phase (Stacey 1977). The natural restorative ability of the South Platte enables it to process a portion of the pollutants introduced upstream, particularly those introduced in the vicinity of Denver.

3 However, this characterization is relative. Runoff from agricultural lands and municipal wastes from several communities along the river introduces additional pollutants that retard the natural processing ability of the stream.

Water for power generation is drawn primarily from the South Platte River. After its utilization in the Station, it is directed to Goosequill Pond via Goosequill Ditch. From Goosequill Pond, it enters the South Platte River approximately 120 m upstream from the confluence of the South Platte and St. Vrain Rivers (Figure 1). Utilization of St. Vrain River water and contingency discharge into it are permitted by the Station's license but have not normally occurred. Thus, the primary monitoring emphasis has been on the South Platte River.

The heated and nutrient-enriched character of the effluent was con-sidered most likely to cause changes in the macroinvertebrate and/or I

fish comunities. Although algicide was used to control algal growth in

) the cooling towers, no specific effort was made to determine its relative effects on aquatic invertebrates.

Addition of heated effluent tends to dampen natural thermal cycles D

or may increase normal summer highs. The particular effect of the heated effluent depends upon the degree of change, the season, and the rate of discharge. Altered temperature may manifest itself in several ways

] depending upon the magnitude and duration of the change. Ward (1976)

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Cl f SP4B C SP4A-0

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Figure 1. Location of sampling sites on the South Platte and St. Vrain Rivers in the vicinity of the Fort St. Vrain Nuclear Generating Station near Platteville, Colorado, May 1974 - December 1979.

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reported reduced diversity but greater biomass of the macroinvertebrate l

! . community .in a themally-constant environment below a reservoir. Many foms are keyed to a particular temperature for initiation of different phases of their life cycles -(Khoo 1968). Other foms are synchronized

! with rather specific numbers of degree days for initiation of different developmental stages (Hynes 1970a). Many invertebrates are adversely I

affected by very slight changes in temperature (Knight and Gauflin 1963, Lehmkuhl 1972, Brittain 1977, Coricum 1978 and Elliott 1978). Sweeney and Vannote (1978) found that warmer-than-normal temperatures accelerated nymphal development; this resulted in acre rapid maturation but smaller adults that were less fecund than their relatives in more " natural" environments. The manifestation of varied temperature requirements 's continuous replacement of one species by another throughout the year.

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l Such a replacement series results in a more diverse invertebrate com-munity as interspecific (and intraspecific) competition is reduced.

I Goosequill Pond serves as a cooling sump for the heated effluent 3

frrO the Station. The constant (or relatively constant) pulse of water through the pond creates a polymictic lentic ecosystem in which nutrients

! are continuously cycled. Agricultural runoff augments the enrichment of

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l the system. Such a situation in association with the introduction of I

heated water from the Generating Station prolongs the growing season of i

l the phytoplankton. Thus, the discharge from Goosequill Pond is enriched

) by the nutrients circulated from the bottom of the pond and by phyto-and zooplankton nurtured in the pond. The impact of the heated and nutrient-enriched discharge upon the fauna of the South Platte River D depends upon the extent of the dilution of the effluent. Enrichment 3-

C 16 may enhance a normally comparatively-sterile environment or may " overload" O

it to the detriment of all but the more tolerant forms.

Distinguishing the relative effects of altered thermal regimes from those of increased nutrient load is probably impossible in the present O

study. Indeed, the effort may be specious as the two are intimately related in the studied system. The effect of the effluent is obviously dependent upcn the extent of dilution; the periodicity, timing, and 9

duration of the discharge; and the characteristics of the effluent as compared to those of the South Platte River.

Station operation began in December 1976 and has continued inter-mittently since then (Table 1). Level of operation per month has varied greatly. Such irregular operation makes correlations between Station operation and changes in aquatic faunal communities rather difficult.

Changes noted may be an artifact of normal, " natural" cycles, or they may be the result of the effects of the effluent.

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Table 1. Number of days of power generation per month of the Fort St. Vrain' Nuclear Generating Station.

1976 1977 1978 1979

1. days w/ # days w/o # days w/ # days w/o # days w/ # days w/o # days w/ # days w/o generation generation generation. generation . generation generation generation generation .

. January --

31 30 1 11 20 28 3 j

February --

29 .-- 28 --

28 1 27 March --

31 1 30 --

'31 -- 31 ,

4 April --

30 7 23 26 4 --

30 May --

31 13 18 29 2 --

31 June --

30 --

-30 24 6 --

30

! July --

31 2 29 26 5 6 25 $

August --

31 14 17 13 18 26 5 Septenber --

30 24 6 .7 23 1 29 October --

31 30 1 13 18 16 15:

Hovember --

30 16 14 29 1 --

30 December 21 10 --

31 23 8 --

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METHODS Aquatic macroinvertebrates were collected by two methods and com-bined for analysis. A triangular aquatic insect net was suspended in the water column below the worker as he traversed the stream for 10 min. A " kick sample" consisteu of those invertebrates disturbed from the substrate which were washed into the net. Organic debris was

" picked" for 5 min. The kick sample was typically subsampled with a O

rotating carousel. However, occasional lack of availability of the subsampler required placing the sample in an enamel pan divided into eight equal sections, spreading invertebrates uniformly throughout the O

pan, and picking one randomly-chosen section. Kick-sample invertebrates were stained with Rose Bengal to facilitate enumeration. The inverte-brates from the kick subsample and pick sample were identified to lowest feasible taxonomic level (usually genus or family). Carlson et #

al. (1974) established pemanent collection sites at SP4A-0, SP48 and C1 in May 1974. Samples were taken at these stations (except SP4A-0) for the remainder of the study. Station SP40 was established as a 8 pemanent site by Carlson, et al. (1975) in April 1975. In July 1977, SP4A-0 was discontinued and SP4A-N was added as a permanent site (Carlsonetal.1977). Sites were selected to enable assessment and 9 evaluation of possible effects of Station effluent upon the aquatic macroinvertebrate fauna in the South Platte River. Thus, one control site was located above the discharge points of Goosequill Pond, and G several experimental sites were below. Beaver activity below Goosequill Pond and abnomally-high discharges occasionally caused Goosequill Ditch to empty into the South Platte River at points other than its nomal gl l

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discharge point. Such exigencies required site movement, discontinuation, and/or addition to ensure the integrity of the-control site.

Annual fish collections comenced at two pemanent stations each on the South Platte'and St. Vrain Rivers in 1975 and continued until the temination of the project. Fish were collected with electro-fishing gear of various models. All fish collected at each site were identi-fied and enumerated. On several occasions, weights and-lengths of some

) 'or all fish were taken. Fish sampling was nomally done in the autumn of each year.

Chemical and physical data were collected at each permanent station 3 on each macroinvertebrate sampling date. Dissolved oxygen and alkalinity were measured according to Standard Methods (APHA et al. 1973).

Turbidity and pH were measured with a Hach Turbidimeter and a Corning 3 pH meter, respectively. Hardness ss measured with a Hach Field Ecology kit. In 1975, filtrable solids, conductivity and dissolved carbon dioxide were added to the parameters measured. Filtrable solids were

) calculated according to Standard Methods (APHA et al.1978), conductivity was determined with a Bechman Con /uctivity Bridge, and dissolved carbon dioxide was estimated with a nomograph. In July 1978, dissolved solids l

determination was added and was measured according to Standard Methods h

(APHA et al. 1973). Air and water temperature were measured with a mercury thermometer.

From 1975 until project termination, the Shannon-Weaver Index of D

General Diversity (Wilhm and Dorris 1968), MacArthur's Index of Equitibility (MacArthur 1957 and Lloyd and Ghelardi 1964), and Brinkhurst's (1968) Trophic Condition Index values were calculated

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1 quarterly for macroinvertebrates using a Fortran IV program, ECODIV, Gl' developed by Galat, Keefe, and Bergersen (1974).

Analysis- of variance tests (A0V) were performed to determine if there were significant differences in selected macroinvertebrate numbers per 9

month for each station for different years and among stations for the same year. The same test was applied to ECODIV values on the same basis.

Water temperatures of the South Platte River were recorded every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> by Public Service Company personnel. These data were made available to the authors for assessment of the effect of possible temperature regime alteration upon the structure of the macroinvertebrate community of the South Platte River. Temperatures were averaged for am and pm readings for each day. Monthly means were calculated for above and below effluent discharge readings. Analysis of variance tests were performed to determine O

if there were significant differences in water temperatures for each month, 1974-1979 ( am and pm; above and below effluent discharge), between stations above and below effluent discharge ( am and pm ) for each month O

(1975-1979), and for each month ( am. and pm; above and below effluent discharge) before (June 1974-November 1976) and after (December 1976-December 1979) initiation of Generating Station operation.

O The data presented herein are a synthesis of work done by five researchers from 1974 through 1979. Whenever one worker replaced another, the two worked together for at least 1 month to ensure continuity of methods. However, some difference in techniques and skills were unavoid- O able. Standardization was enhance by one person (C. A. Carlson) reviewing all work and constantly assessing the methods and techniques of each W. Don Frank served as c special consultant to confirm identifi- O worker.

cation of unusual or difficult-to identify macroinvertebrates.

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) 21 RESULTS l D

Macroinvertebrates The macroinvertebrate comunity of the South Platte River near the Fort St. Vrain Nuclear Generating Station is composed 1.-imaril;, of taxa tolerant of at least moderate pollution levels. The serus of collec-tion stations had similar faunas each season and each year. Differences resulted primarily from rareYeollected unusual forms and changes in D Similarities were the relative abundance of some more-common forms.

more marked prior to power plant operation than after. Within the sampling area, the habitat was rather uniform among stations; thus, O differences would normally be minimal. With the initiation of effluent discharge into the South Platte River from Goosequill Pond, changes were apparent in the macroinvertebrate comunity below the diwharge D point.

An annual periodicity of abundcnce of individuals and taxa was observed (Table 2). Fewest taxa were collected at all stations in 1975 O and 1976. Relatively-low numbers were collected at SP4B and Cl in 1977.

In 1978, there was a marked increase in taxon numbers at all stations.

In 1979, fewer taxa were collected at all stations, except SP4B, but D numbers were not as low as in 1975 or 1976.

Seasonal cycles in taxon numberr were observed. In sites unaffected by Station effluent and affected sites prior to Station operation, O an early peak in numbers occurred in February with a subsequent diminu-tion in March and a gradual increase through June. In July, taxon numbers reached rather high levels and generally remained high through 3 October. By November, taxon numbers began to decrease and reached low levels in December comparable to those collected in January (Figure 2).

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l Table 2. Number of taxa collected each month for each station during l the study, 1974-1979. l O

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec SP4A-0 1975 14 12 10 11 10 12 4 16 14 14 11 10 ,

1976 8 8 3 9 5 9 15 19 13 12 12 9 1977 2 8 9 7 11 12 SP4A-N 1977 18 14 17 18 13 12 ,

1978 9 9 12 10 14 18 17 21 21 18 18 7 1979 10 11 14 11 14 --

16 16 14 14 10 5 SP4U 1975 6 9 2 7 12 16 10 15 10 1976 8 8 3 9' 5 8 20 21 10 13 13 5 1977 6 10 6 8 11 15 16 14 14 16 14 9 1978 10 11 12 13 9 13 16 19 18 22 12 8 1979 11 12 15 12 13 --

15 15 13 14 12 11 O

SP4B 1974 10 17 18 23 20 18 14 16 1975 12 17 14 10 11 4 9 13 13 13 13 10 1976 7 12 9 8 8 9 13 16 15 9 9 10 10 15 16 15 12 1977 5 11 8 8 8 15 17 1978 8 11 7 10 17. 14 17 16 17 20 17 7 1979 12 16 11 16 17 --

17 16 18 19 12 10 C1 15 19 19 16 19 11 13 8

1974 11 1975 19 15 12 16 11 3 6 17 15 15 19 10 1976 9 13 7 5 9 11 13 13 9 11 11 8 1977 6 10 5 7 10 10 13 11 10 14 11 12 1978 10 9 10 7 11 16 15 20 21 17 16 4 8 1979 12 14 11 12 11 --

17 15 14 13 16 10 O

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J F M A M J J A S 0 N D Figure 2. Mean number of taxa collected each month at each station during the study, 1974-1979.

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24 The nomal cycle of taxon numbers changed at SPtB and Cl after Generating Station operation began,although the pattern persisted. Taxon number e increase occurred earlier, and the high number lasted longer.

Normally, the macroinvertebrate community of a site was composed g of a few rather-abundant organisms and a number of rarer, less-comon forms. Since 1974,133 macroinvertebrate taxa have been collected in the South Platte River (Table 3). Of these, 83 (62%) were very rare, ,

28 (21%) were rare,12 (9%) uncommon, 7 (5%) comon, and 3 (2%) abundant.

Although eight orders of insects and six non-insect invertebrate groups were collected in the study area, two groups, Diptera and ,

Oligochaeta, dominated the collection. Dipterans were the most speciose group, and Chironomidae were the most abundant in numbers and taxa.

Siraliidae were generally common. Of the remaining insect taxa ,

collected, only Baetis sp. (Ephemeroptera: Baetidae) and Hydropsyche sp. (Trichoptera: Hydropsychidae) were comon. Hyalella azteca (Amphipoda: Talitridae) was the only comon non-insect besides the O

Oligochaeta. Cladocerans were extremely abun0nt in t' ne autuma of 1979 but were quite uncomon or absent in all other years.

Differences in diversity and biotic index valuer, were often O.

significant for the same quarter emong years (Figure 3), but similar trends in values were observed through the year for each site (Figure 3a). Thus, the second quarter (April - June) normally had che lowest values and the 9

third quarter (July - September) had the highest. Analysis-of-variance tests did not demonstrate significant differences in index values for a l particular site for each year (except EQUIT in 1979) (Table 4). How-i O ever, significant F statistics were frequently obtained when A0V was O

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25 Table 3. Aquatic macroinvertebrates collected in the South Platte Rive'r

.in the _ vicinity of the Fort St. _Vrain Nuclear Generating

)_ ~ Station, sites collected,. years collected and relative abundance.

Sites' Years Relative Taxa

' collected collected abundance Collembola Isotomidae VR Isotomurus palustris SP4A,SP4U.SP.4B.C1 74,77,78,79 l

Plecoptera

} Periodidae SP4A(_N),SP4U 78 VR Ephemeropters Giphlonuridae l Siphlonurus sp. SP4A,SP40,SP48,C1 74,76,77,78 R 75 VR Ameletus sp. SP4B

- ' Baetidae Baetis_sp. SP4A,SP4U.SP4B,C1 74,75,76,77,78,79 C t

Callibaetis sp. CP4A(N),SP4B,Cl 74 VR I

Centroptilum sp. SP4A,SP48,C1 74,75 VR j' Paracloeodes sp.

Pseudocloeon sp.

SP4A.SP40,SP48,C1 SP4A(0),SP4U.SP4B 75 74 VR R

Heptageniidae

! Heptagenia_.sp. SP4A,SP4U,SP4B,Cl 74,75,76,77,78,79 UC I Leptophlebiidae Paraleptophlebia sp. C1 76 VR Traverella sp. SP4U,Cl 77 VR Tricorythidae

) Tricorythodes sp. SP4A,SP4U.SP48,C1 74,75,76,77,78,79 UC Caenidae Caenis sp. SP4A(N),Cl 77 VR Odonata Gomphidae Ophiogomphus sp. SP4A.SP48,C1 74,75,77 R D SP40,C1 76,77,79 VR I Coenagrionidae Argia sp. SP4A(N),SP4U,SP4B,C1 74,75,77,78,79 R Hyponeura sp. SP4B 74,75 VR Amphiagrion sp. SP4A(N),C1 78,79 VR Ischnura sp. SP4A,SP4U.SP48,Cl 74,76,77,78,79 R 3 Enallagma sp. SP4A(0),SP4U,SP48,C1 74,75,7(,77,78 R Anomalagrion sp. SP48,C1 74,77 VR l

Hemiptera Gerridae Gerris sp. SP4A(0),SP4U,SP48,C1 74,77 R D Veliidae Microvelia sp. SP4A(0),SP4U,SP48 76 VR

, Notonectidae Notonecta sp. SP4B,C1 74,75 VR 3

26 O

Table 3. Continued.

I Taxa Sites Years Relative collected collected abundance Corixidae SP4A,SP4U,C1 73,77,78,79 R Trichocorixa sp. SP4A,SP4U,SP48,C1 h ,77,78 R Corisella_sp. SP48,Cl 74 VR S Cenocor1xa sp. SP4A(0),SP4U.SP48,C1 74,76,77,78 R Trichoptera Trichoptera pupae SP4U 78 VR Hydropsychidae Hydrophyche sp. SP4A,SP40,aP48,C1 74,75,76,77,78,79 C 9 Hydroptilidae Mayatrichia sp. SP4A(N),SP4B 77 VR Agraylea sp. SP40,Cl 78 VR Ochrotrichia sp. SP4A(N),SP4U,SP4B,Cl 78,79 UC Coleoptera e Haliplidae SP4U 77 VR Peltodytes sp. SP4A(0) 75 VR Dytiscidae SP4U.SP4B,C1 78,79 VR Dytiscus sp. SP4A(0),SP4B 74,79 VR Laccophilus sp. SP4A(N),SP4B 74,75,79 R Agabinus sp. SP4U 79 VR e Agabetes sp. SP48,Cl 78 VR Matus sp. SP4A(0) 74 VR Noteridae SP4B 79 VR Corrhydrus sp. SP4A(0),SP48,C1 74 VR Coptotomus sp. Cl 74 VR Rhantus sp. SP4A,SP4U SP48,C1 77,78 R g Hydrophilidae Helophorus sp. SP4A(N),SP4U SP48,C1 78,79 R Tropisternus sp. SP4A(0),SP4U.SP48,C1 74,75,76 R Hydrophilus sp. SP4A(0) 76 VR Enochrus sp. Cl,SP4B 75,76 VR Laccohius sp. SP48,Cl,SP4A(0) 75 R g Hydrobius sp. Cl 74 VR Diptera Tipulidae SP4A,SP40,SP4B,C1 75,76,77,78,79 R Tipula sp. SP4A(N),SP4U,SP4B 77,78 VR Pedicia sp. Cl 79 VR Hexatoma sp. SP4A(N),SP48,C1 78,79 VR Psychodidae SP4A(N),SP4U SP4B,C1 75,76,77 R Psychoda sp. SP4A(N),SP4U,SP48 79 VR Simuliidae Simuliidae pupae SP4U 78,79 R Simulium sp. SP4A,SP4U.SP48,C1 74,76,76,88,78,79 C Chironomidae SP4A,SP4U,SP4B,C1 78,79 UC #

Chironomidae pupae SP4A,SP4U,SP48,C1 7),78,79 UC Tanypodinae Tanypus sp. SP4A 77,78 VR Procladius_sp. SP4A(0),C1 75,76 VR 9

9 27 Tabla 3. Ccntinued.

O Relative Sites Years Taxa abundance collected collected 75 VR Clinotanypus sp. SP4A(0)

Conchapelopia sp. SP4A,SP4U,SP48,Cl 74,76,76,77,78,79 UC 9

Diamesinae Diamesa sp. SP4A,SP4U,SP4B 75,76,77,78,79 R Pseudadiamesa sp. SP4B 76,78,79 VR 77 VR Pottnastia sp. SP4B 78 VR e Monodiamesa sp. SP48 Orthocladinae Brillia sp. SP4A(0),SP4B,C1 74,75 VR Thienemanniella sp. SP4A(N),Cl 78,79 VR Smittia sp. SP4U 79 VR Eukiefferiella sp. SP4A(0),SP4U.SP48,C1 75,76 VR Psectrocladius sp. SP4A,SP4U,SP48,Cl 74,76,77,78,79 R Cricotopus sp. SP4A,SP4U.SP48,C1 74,75,76,78,79 A Ortnocladius sp. SP4A,SP48,Cl 74,75,76,77 R Nanocladius sp. St. Vrain Heterotrissocladiussp.SP4A(0),Cl 74,75,76 VR Trichocladius sp. Cl 79 VR Dipiocladius sp. SP4U 78 VR Chironominae Chironomus sp. SP4A,SP4U.SP48,C1 74,75,76,77,78,79 C Cryptochironomus sp. SP4A.FP4U,SP4B,C1 74,75,76,77,78,79 UC Glyptotendipes sp. SP4A,SP4U.SP43,Cl 74,75,76,77,78,79 UC Dicrotendipes sp. SP4A,SP4U.SP4B 74,75,76,77,78,79 C Polypedilum sp. SP4A,SP4U,SP48,Cl 74,75,76,77,78,79 C Stictochironomus sp. SP4A(0),SP4U,SP4B,Cl 74,75,77,78 VR Kiefferulus sp. SP4A(N) 77 VR Phaenopsectra sp. SP4A(0),SP4U.SP4B,C1 75,76,77,79 VR Parachironomus sp. SP4A(0),SP4U.SP4B,Cl 74,76,78,79 VR Paracladopelma sp. SP4A(0),SP48,Cl 74 VR Micropsectra,sp. SP4A,SP4U,SP48,Cl 74,75,76,79 R J

Par: auterborniella sp. SP4A,SP4U.SP46,C1 75,76,77,78,79 UC Tanytarsus_sp. SP4A,SP4U SP4B,C1 75,76,77,78 UC Rheotar.ytarsus sp. SP4A(N),SP4U.SP4B,C1 77,78,79 R Pseudochironomus sp. SP4A(N),SP4U.SP48,Cl 77,78 R Endochironomus sp. SP4A(N),C1 75,76,77 VR Goeldicrironomus sp. SP40 79 VR Ceratopogonidae SP4A(N),SP40 76,79 VR Palpomiyia sp. SP4A(0),Cl 78 VR Stratiomyidae SP4A(N),SP4U,SP4B,Cl 74,79 VR Tabanidae SP4A(0),SP4U.SP4B 74,75,76,78 VR Tabanus sp. Cl 75 VR Athericidae Atherix sp. SP4A(0),SP48,C1 74 VR Dolichopodidae SP4A(0),SP40,C1 75,76 VR Empididae SP4B 76 VR Syrphidae SP4B 74 VR

l C

28 j l

Table 3. Continued.

Taxa Sites Years Relative collected collected abundance Ephydridae SP4A SP4U.SP48,Cl 76,77,78 R Brachydentera sp. SP4U 78 VR 74,75,76,78 VR O Muscidae SP4A,SP4U,SP4B,C1 Limnophora sp. SP4A(N),SP4U.SP4B 77 VR Scatophagidae (=Anthomyiidae) SP4A(0),SP48,Cl 74 VR Coelenterata Hydroida SP4B,Cl 78 VR O

Turbellaria Tricladida Planariidae SP4A(N),SP4U SP48,Cl 77,78,79 VR Duaesia sp. SP4A(0),SP4U 76 VR SP4A(N),SP4U.SP48,Cl 79 VR G Nematoda Nematomorpha SP4A(N) 79 VR Annelida Oligochaeta SP4A,SP4U.SP48,C1 74,75,76,77,78,79 A O

Hirudinea' SP4A,SP48,Cl 78,79 VR Pharyngobdellida Erophdellidae SP4A(0),SP4U 74,78 VR Eropbdella sp SP48,C1 74 VR Crustacea e C1adocera SP4A(N),SP4U,SP48,Cl 79 A*

Daphnidae SP4A N),SP4U,SP4B,C1 78,79 R Daphnia sp. SP4A N),SP4B 79 R Copepoda SP4A N),SP4U,CP48,C1 78,79 VR Cyclopoida SP48 79 VR Ostracoda SP4B 78 VR g Isopoda Asellidae Asellus sp. SP4A(N),SP4U.SP4B,Cl 77,78,79 VR Amphipoda Talitridae Hyalella azteca SP4A,SP4U.SP4B,C1 74,75.76,77,78,79 C g Ganmaridae Ganmarus sp. SP4U 79 VR Crangonyx sp. SP4A SP4U,SP4B,Cl 74,75,76,77,78,79 UC Decapoda Astacidae Camborus sp. SP4A(0),SP4U,SP48,Cl 74,75,76,77,78 R g

• Cladocera extremely abundant on dates collected.

O

)-

29. .

i Table 3. Continued.

Sites Years Relative Taxa -abundance l

collected- collected Gastropoda Physidae Physa sp. SP4A.SP40,SP4B,Cl 74,75,76,77,78,79 UC

f. Lymnaeidae i Lymnaea sp. .SP4A(0),SP48,C1 74,77,78 UR

! 133 taxa total 83 taxa VR = 62%

f 28 t3xa R = 21%

12 taxa UC = 9%

7 taxa C= 5%

3 taxa A= 2%

Very Rare (VR): collected in only one year in very low numbers (<10) on t

l one or more sampling dates at one station and/or collected in several years on one or more sampling dates at one or more stations in extremely low numbers (<5).

Rare (R): collected at one or more sampling sites on one or more sampling

). dates in several years in low numbers (<25).

Uncomon (UC): collected at several sampling sites on several sampling dates in most to all years in generally low to moderate l

i numbers (10-100).

)

l Comon (C): collected at most sites on most samplinc dates in most years in moderate to high numbers (25-250s.

1 .

Abundant (A): always (or almost always) collected on all sampling dates at all sampling sites in all :ars in moderate to extremely high numbers ( 25).

A b; .

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_mFf~~ r-(Continued on next page)

Figure 3. C'versity and Biotic Index values for each quarter at four sampling stations on the G .th Platte River, Colorado.

O e e e e e e e e e e

31 F

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32 0 Table 4. A0V comparison of ECODIV values by year in a downstream direction. ECODIV values are for all sites and all quarters.

H F F Reject?

g s t TCI 1975 No difference in ECODIV value 0.0469 3.59 No g for year among sites 1976 0.5339 3.49 No 1977 0.0933 3.36 No 1978 0.1676 3.49 No g 1979 0.0779 3.49 No DBAR 1975 0.1193 3.59 No e 1976 0.1367 3.49 No 1977 1.4298 3.36 No 1978 0.2534 3.49 No 3 1979 6.i154 3.49 EQUIT 1975 0.0212 3.59 No 8 1976 1.1985 3.49 No 1977 0.8634 3.36 No 1978 0.3871 3.49 No e 1979 4.2415 3.49 Yes I

H = null hypothesis.

g 2 O F = calculated F statistic.

3F t' = table F statistic.

9 G.

3 33 perfonned.to analyze differences for the same quarter among stations j (Table 5).

I Statistical anslysis of other aspects of invertebrate numbers, l relative abundance, and taxon numbers by several approaches failed to demonstrate significant changes .among stations or through the years at 3

L a particular station.

Fishes 3 Annual fish collections at two sites each on the South Platte and St. Vrain Rivers showed no significant changes in the fish community of either stream in this study. Twenty-five species representing eight

3 families were collected (Tables 6 and 7). Four species (Salmo gairdneri_,

Hybognathus hankinsoni, Fundulus sciadicus_ and Micropterus dolomieui) were found only in the St. Vrain River. None was comon. Minnows

D (Cyprinidae) were the most speciose family and most numerous fish in f both streams in all collections. The number of speck.s collected bore a strong relation to the intensity of sampling effort. Never were all D species collected during the study present in one sample. Notropis  ;

stramineus was normally the most abundant species. Game fish were never abundant, and the few captured were always rather small.

I La l

Sampling Stations SP4A-N and 0 The location of SP4A was moved in 1977 because of effluent dis-l m

charge near SP4U. From 1974 through June 1977, SP4A was immediately

[

above the primary effluent discharge point. In July 1977, SP4A was relocated opposite Goosequill Pond (SP4A-0 designates the pre-July 1977 and SP4A-N the post-July 1977 loc Mion of SP4A). Although major i differences in the macroinvertebrate communities of the two sites were i

1

34 O' Table 5. A0V comparison of EC0DIV values of four sites on the South Platte River. ECODIV values are based upon quarters, and F Statistics are calculated for comparison of sites in a

downstream direction for each quarter.

I F 2 p Reject?

Hg 3 t TCI J-M Each site is not 59.7157 3.11 Yes significantly different A-J 454.3557 3.06 Yes J-S "

45.4451 3.06 Yes 0-D 45.5131 3.06 Yes O

DBAR J-M 47.8563 3.11 Yes O

A-J 36.1712 3.06 Yes J-S 66.0255 3.06 Yes 0

0-D 58.2430 3.06 Yes EQUIT e J-M 2.3120 3.11 No A-J "

1.3645 3.06 No 9

J-S "

17.3845 3.06 Yes 0-D 11.8146 3.06 Yes 9

I Hg = null hypothesis.

l 2

l Fs = calculated F statistic.

3 7 = a e stad sd c.

t O

y -

i 35 Table 6. Ichthyofauna of St. Vrain Creek in the vicinity of the Fort

. St. Vrain Nuclear-Generation Station,1975 to 1979.

l 1975 1976 .1977 1978 1979

1. /% #/% #/% .#/% #/%-

j. Dorosoma cepedianum

.Cyprinus carpio-1/0.3 6/1.3 64/18.9 496/44.6 3/0.3 26/1.9 .62/1.4 l' Pimephales promelas 39/8.7 - 12/3.5~ 43/3.9 250/18.3'106/2.4

(

Notropis lutrensis 66/14.7 11/3.2 6/0.5 14/1.0- 595/13.6 15/1.1 73/1.7 N_. dorsalis "

_N. stramineus 270/60.3 88/26.0 164/14.8 939/68.6 3288/75.4 Hybognathus hankinsoni 9/0.7 12/0.3

-N. stramineus x H. hankinsoni

) Semotilus atromaculatus 1/0.2 4/1.2 3/0.1 Rhinichthys cataractae 6/1.8 2/0.2 18/1.3 62/1.4 Campostoma anomalum 4/0.3 4/0.1 l _ Cyprinidae hybrids 37/10.9 C Catostomus catostomus '4/1.2 75/6.8 2/0.1 8/0.2

~C. connersoni 41/9.2 59/17.4 172/15.5 53/3.9- 88/2.0 Ictalurus melas 1/0.3- 5/0.1' Fundulus kansae 1.0.3 10/0.9 23/1.7 11/0.3 O- F. sciadicus l

l Culaea inconstans 3/0.7 2/0.1 1/>0.1 Lepomis cyanelius 22/4.9 39/11.5 117/10.5 13/1.0 34/0.8 l humilus 1/0.3 2/>0.1

-L.

l 7 L. macrochirus 1/0.1 l Pomoxis, annularis 3/09 4/0.1 P. nigromaculatus 2/0.2 Perca flavescens .5 13/1.2 Micropterus salmoides i/0.3 1/>0.1 O-

, M_. dolomieui 2/0.6 7/0.6 Total # specimens 448 339 1111 1368 4359 Total # species 8 18 14 13 18 Q ,

o--

36 C Table 7. Ichthyofauna of the South Platte River in the vicinity of the Fort St. Vrain Nuclear Generating Station,1975 to 1979.

9 1975 1976 1977 1978 1979

1. /% #/% #/% #/% #/%

Dorosoma cepedianum 1/0.5 0

Salmo gairdneri Cyprinus carpio 18/5.2 54/29.0 75/17.4 23/3.2 133/5.1 Pimephales promelas 52/15.0 20/10.8 35/8.1 217/29.8 123/4.8 Notropis lutrensis 38/11.0 2/1.1 6/0.8 290/11.2 32/4.4 147/5.7 8

N. dorsalis 5 stramintus 172/49.7 31/16.7 197/45.6 388/53.2 1759/68.6 Semotilus atromaculatus 2/0.6 1/0.5 1/0.2 2/0.1 Rhinichthys cataractae 10/2.9 2/1.1 16/3.7 1/0.1 5/0.2 Campostoma anomalum 5/0.7 8 Cyprinidae hybrids 45/13.0 Catostomus catostomus 7/3.8 12/2.8 3/0.4 2/0.1 C. commersoni 5/1.4 57/30.6 72/16.7 4/0.5 54/2.1

-C. cctostomus x e C. comersoni 2/0.1 Ictalurus melas 1/0.3 6/1.4 2/0.1 Fundulus kansae 6/1.4 53/7.3 28/1.1 Culaea inconstans 2/0.1 g Lepomis cyanellus 3/0.9 9/4.8 12/2.8 1/0.1 29/1.1 L. humilus L_. macrochirus 8/0.3

-L. cyanellus x 8 L. gibbosus 1/0.1 Pomoxis, annularis P_.

nigromaculatus 1/0.5 Perca flavescens 1.0.5 Micropterus salmoides 1/>0.1 #

Total # specimens 3461 186 432 729 2587 Total # species 10 12 10 12 16 9

i

.Il

37 I not observed, some differences were detected and are at least partially

)

explained by the relocation of collection points.

Dipterans and oligochaetes were the preponderant groups found at i

both SP4A sites. Chironomidae was the most speciose dipteran family.

More genera of Chironomidae were found at SP4A-N than at SP4A-0. How-l 3

ever, none of the genera unique to SP4A-N was very abundant or found l

throughout the year. In 1975 and 1976, Cricotopus sp. had two periods j of maximum abundance, but the 1975 peaks were more equal in numbers and duration (Figure 4). In 1978, they were extremely abundant from June through November, but in 1979 peak abundance occurred early in the year followed by a lower peak in late stener. Polypedilum'sp. and j

Paralauterborniella sp. had abbreviated periods of peak abundance in the sumer at both SP4A sites (Figures 5 and 6). Chironomus sp. normally had a sumer high but were found in other months in varying numbers (Figure 7). Dicrotendipes sp. was usually more abundant earlier in the year than at any other time, but the pattern was not absolute (Figure 8).

I L Conchapelopia sp. had no obvious pattern of appearance or abundance J

l (Figure 9). At SP4A-0, Simulium sp. were never particularly comon; f

they were frequently abundant at SP4A-N and evidenced two periods of high numbers (Figure 10). No other dipterans were commonly collected at

, J_

either SP4A-0 or SP4A-N.

Hydropsyche .sp. and Baetis sp. were the only non-dipteran insects comonly collected at both SP4A sites. Baetis sp. were normally y

collected in a rather restricted period in moderate to high numbers at

! both sites (Figure 11). Hydropsyche_sp. were found in most months but t

were typically most abundant in the first and last quarters of the O

year (Figure 12).

j'<A fi<![ C b f r!b

l 38

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Figtre 4. Number of Cricotopus sp. collected each month at four stations on the South Platte River, 1974-1979. mm m 9 3 ao a .

e

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Figure 5. Number of Polyoedilum sp. collected each month at four stations on the South Platte River, 1974-1979.

] ,

40 v.. o C

v . v. _

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el Figure 6. Number of Paralauterborniella sp. collected each month at four stations on the South Platte River, 1974-1979.

mm o ,

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moo o

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Figure 8. Number of Dicrotendipes sp. collected each month at four stations on the South Platte River, 1974-1979. ,

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Figure 9. Number of Conchapelopia sp. collected each month at four stations O on the South Platte River, 1974-1979.

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.JFMAR JJ45049-. 4FMA RJJAleeO Figure 10. Number of Simulium sp. collected each month at four stations on the South Platte River, 1974-1979.

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Figure 11. Number of Baetis sp. collected each t four stations on I

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l 0,

46 O

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s- 5 E M _ r e - N N I m_ ~ m_

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a L4 nf r-m r , _

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, , 1 .q 9 b n, D-n r i I JL M n rm - M e

Figure 12. Number of Hydropsyche sp. collected each month at four stations on the South Platte River, 1974-1979. O

. D *

• lD lD II3llY E e m M o M UJ ll %

• P 47 Hyalella azteca and Oligochaeta were the only non-insect macro-invertebrates comonly collected. Hyalella azteca was found throughout

' the year at both sites, and bimodal cycles were evident in most years i

at both sites (Figure 13). At SP4A-0, 011gochaeta had distinct bimodal O annual cycles with the second peak much narrower and lower than the first and preceeded by very brief periods of extremely-low numbers.

At SP4A-N, peaks were considerably lower than at SP4A-0. The annual O pattern at SP4A-N was similar to that at SP4A-0 but less distinct (Figure l

l 14).

Odonata, Hemiptera, and Coleoptera had relatively few representa-J tives at SP4A, and none was comon. One representative of Plecoptera (Periodidae) was collected at SP4A-N in 1977. Cladocerans were found f in very high numbers in October 1979.

D Slightly more taxa were found at SP4A-N than at SP4A-0. Most taxa found at SP4A-0 were found at SP4A-N, but most rare taxa at SP4A-N were not collected at SP4A-0. Taxon numbers were normally greater in b the second half of the year at both sites.

Community diversity index values were usually highest in the third quarter and lowest in the second (but occasionally the fourth) quarter of the year. Biotic index values approximated diversity index values.

3 The patterns were similar at both sites.

SP4U --

g Data collection was initiated at SP4U in 1974. The site was selected to provide a control site above any possible influence of effluent from Goosequill Pond. Unfortunately, seepage from the pond was observed in the vicinity of the site in June 1977. Since then, flow y

has _only been detected a few times entering the South Platte near SP40.

3.w ,

O $ '

48 v , w= . n C i

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an 77u .".:

e 7

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x.  : tf i i I A F'ln_ :r 4 m

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,l Figure 13. Number of Hyalella azteca collected each month at four stations on the South Platte River, 1974-1979.

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. _/S nm Jf4A nJ e45eea A m F_rd L a b _A-JFnauJJa5000 JFmaaJJA $08 8 JFMA4JJ 458e0 Figure 14 Number of Oligochaeta collected each month at four stations on the South Platte River, 1974-1979.

O D"* DI D TYM

'owb o 1kL

50 g";

1 Despite possible contamination by water from Goosequill Pond, the effect was probably negligible. e Station SP4U was the lealt speciose of the four stations, which is at least partially a function of the short time samples hav! been taken from it. However, the channelized bed morphology would 1:end to ,

make the environment less tenable for many forms. Numbers of taxa collected each year at SP4U were similar to all other stations every year (except SP48,1979). ,

In most respects, SP4U was similar to all other stations. Dipterans, particularly Chironomidae, and oligochaetes dominated the invertebrate fauna. A relatively-high proportion of the chironomid genera present ,

at SP4U were classified as common. Six of 22 genera occurred every year, and two were common in all years except 1975 (Table 3). Thus, SP4U had a rather small number of very rare genera of Chironomidae.

O Cricotopus sp. was found in all months of every year but was quite abundant June - November; in 1979 the greatest number of Cricotopus sp.

was collected in February and March. Thus, except for 1979, Cricotopus 9

sp. abundance followed a constant pattern through the study (Figure 4).

Polypedilum sp., Paralauterborniella sp. and Dicrotendipes sp. had distinct, short periods of occurrence, when their numbers were high.

O Their periods of abundance remained relatively invariable throughout the study (Figures 5, 6 and 8). Conchapelopia sp. followed a similar pattern during the study, but in 1979 they were collected more randomly 9

anti in generally low numbers (Figure 9). Chironomus sp. had a pattern of peak abundance similar to those of the above genera, but its periods of abundance were not as sharply delineated and tended to vary among e

years (Figure 7).

O

) 51 Early in the study, Simulium sp. occurred in relatively-low numbers j

) and demonstrated no readily-discernable pattern. However, in 1978 and 1979 they were significantly more abundant and had two periods of peak abundanceeachyear(Figure 10).

Baetis sp. had a fairly-consistent, strict, seasonality of appearance. However, numbers were much greater in 1978 than in other years (Figure 11). Hydropsyche sp. were most abundant in the winter months (Figure 12).

! Hyalella azteca did not follow any obvious pattern at SP4U. A trend detectable one year would be essentially reversed the next (Figure 13). Oligochaetes were extremely abundant in several months in 1975 and 1976. Their numbers were quite high in early sumer in all years except 1979 (Figure 14).

All groups found at SP4U had few taxa per group. Comunity 3

diversity was normally greatest in the third quarter of each year and l lowest in the second. Biotic index values roughly paralleled diversity index values (Figure 5).

SP48 --

S'tation SP4B, located imediately below the discharge point of l

I l Goosequill Ditch, was considered to be the site at which the possible D

j effects of effluent upon the macroinvertebrate comunity would be most readily detectable. More taxa (,108) were collected from SP4B than any l other site. However, in each year the number of taxa collected at SP4B h was not significantly different from the numbers collected at other l stations.

All major groups had representatives at SP4B. As at other stations, D dipterans were the most speciose group; they and oligochaetes dorinated D

52 O the invertebrate community. A rather large number of dipteran families were collected at SP48, but only Simuliidae and Chironomidae were com-O monly collected. Cricotopus sp. was frequently the most common organism collected. They were found throughout the year in large numbers but were most abundant during the summer and early autumn (Figu"e 4).

O Other chironomids typically had more distinct periods of seasonui appearance. Polypediluin sp. and Paralautercornf ella sp. were collected primarily in the summer and in high numbers (Figure 5 and 6). The timing of their short period of abundance did not appear to change over the years. In contrast, Chironomus sp. and Dicrotendipes sp. were present in low numbers when found early in the study; they generally became more seasonally restricted but present in much higher numbers later in the study (Figures 7 and 8). Conchapelopia sp. occurred through-out the year but in rather low numbers (Figure 9).

Simulium sp. abundance during the study followed a more complex pattern. Early, they were present in most months but in low numbers.

In 1977, they were distinctly more abundant in November and December.

However, in 1978 and 1979 they were most abundant in January and February, indicating a slight shift in time of hatching (Figure 10).

Baetis sp. were present in relatively large numbers only in the sumers of all years (Figure 11). Hydropsyche sp. were usually present 8 throughout the year in varying numbers. A tendency towards peak abun-dance in early spring and late autumn-winter was noted (Figure 12).

Among non-insect invertebrates, only Hyalalla azteca and Oligochaeta 8 occurred consistently throughout the study. 011gochate numbers were extremely high in the spring and early suraner of 1975-76. In subsequent years, numbers decreased and were roughly similar in all seasans (Figure O 14). Hyalella azteca was nonnally present during all seasons but O

. 53 typically had two peaks of abundance; late spring and early-to-late-

) autumn (Figure 13). Cladocerans were extremely abundant in October 1979 but were not collected in any other year.

Odonata, Hemiptera, and Coleoptera had no representative that was 3 found every year. Most taxa within these groups were found irregularly and often only once. Heptagenia sp. (Ephemeroptera: Heptageniidae) and Tricorythodes sp. (Epheceroptera: Tricorythidae) were considered D uncomon inhabitants of SP48 but were collected in the suscrs of all years in low numbers. Ochrotrichiasp.(Trichoptera: Hydroptilidae) were collected only in the autumn of 1978 at SP48.

The mean number of taxa collected per month during the study was

?

generally slightly greater at SP4B than at other stations. An early peak in taxon numbers occurred in February and was followed by a low in March. Subsequently, taxon numbers steadily rose through September and 3

then declined to a December low comparable to the January low (Figure 2).

When the average number of taxa per month before initiation of Generating Station operation was compared to the number after initiation, the patterns 3

of abundance were the same but the phase was different (Figure 2b).

Community diversity as measured by EQUIT and DBAR followed a seasonal pattern similar to taxon numbers, as would be expected. Prior g

to Station operation, diversity was lowest in the second quarter and increased to a maximum in the third quarter. After Station operation began, the trend changed. Beginning in 1977, the lowest diversity index y

values were in the first quarter and steadily increased through the year. However, in 1979 the fourth quarter values were lower than the third quarter values (Figure 3). Except for 1977, TCI values followed J j the same pattern every year.

l

)

54 U

SP4B had a lower percentage of very rare taxa than recorded for all other stations but a higher proportion of rare and uncommon taxa. 9 C1 --

The location of C1, irmiediately below the confluence of the South Platte and St. Vrain Rivers, is such that possible effects of the b effluent would be mitigated by the St. Vrain River. Thus, themal and nutrient introductions to the South Platte via Goosequill Ditch are diluted by the St. Vrain River. Cl had the most monotonous substrate 9 (sand) of any station, the highest average flow, and the lowest deposi-tion of organic debris. For these reasons, it might be expected to have the fewest taxa and the lowest diversity of the stations sampled.

O However, Cl harbored the second-highest number taxa of the stations, and community diversity there was comparable to or higher than at all other stations except SP48. All major groups had representatives at Cl, but O

total number of organisms collected was generally lower than the number collected at other stations for any specific sampling date.

Dipterans were the most speciose group at Cl, and Chironomidae had the most genera (27). With oligochates, chironomids normally dominated the macroinvertebrate comunity of C1. Cricotopus sp. were generally present throughout the year but in widely-fluctuating numbers.

No obvious pattern o_f seasonal abundance was discernable prior to 1979; peak abundance periods changed from year to year in a rather random manner. In 1978, Cricotopus sp. numbers increased to a late-sumer or early-autumn high and rapidly decreased in November (Figure 4).

Polypedilum sp. occurred from May to November. However, in any particu-lar year they were collected during a much briefer period (except in 1976, when none were collected) (Figure 5). Paralauterborniella sp.

was usually collected in a short period of the year in high numbers.

O

)

l 55-l However, in 1979 they were only collected in January in low numbers j; (Figure 6). The Dicrotendipes sp. abundance pattern changed perceptibly during the study. In 1974,1975, and 1976, they were collected through-out the year. In 1977, there was a marked shift to October-December.

In 1978 and 1979, they were found only in the early months of the year 3

(except one species collected in August 1979) (Figure 8). Chironomus sp.

f were irregularly present in.high numbers prior to 1970. However, in 1978 l

they appeared more consistently throughout the year in moderate numbers.

3 In 1979, they occurred less frequently in rather low numbers (Figure 7).

Conchapelopia sp. were found in all years in low numbers in most seasons.

No discernible pattern was observed in their occurrence (Figure 9).

The Simulium sp abundance pattern underwent rather distinct changes during the' study. Early (1974,1975, and 1976), they were present most of the year in low numbers. From 1977 through 1979, peak abundance b

occurred in the winter (Figure 10)..

Hydropsyche sp. generally were found throughout the year, but rarely in high numbers. Their abundance increased slightly in the later years of the study (Figure 12). Baetis sp. generally had a rather restricted period of occurrence (July-October) and were not particularly CoCEon.

Hyalalla azteca had bimodal cycles of abundance in most years, but the pattern was more evident early in the study (1975 and 1976). In 1978, they appeared throughout the year in relatively constant numbers.

U In 1979, a bimodal pattern appeared to be re-established (Figure 13).

l~

)

1 l

56 (j ;

i In 1974, 1975, and 1976, oligochaetes were extremely abundant in several months of each year; they decreased to comparatively low O

numbers in 1977 and never oce.urred in excessively high numbers in the remaining years of the study. Relative late-sumer or early-autumn and early (January-March) lows were noticeable in all years (Figure 14).

O No Odonata, Hemiptera, or Coleoptera taxa were commonly collected or found every year. Other than taxa discussed, none was found regularly during the study in significant numbers. Hytagenia sp. , Tricorythodes e

sp.,Cranganyxsp.(Amphipoda: Gammaridae) and Physa sp (Mollusca:

Physidae) were the only other organisms to occur every year. However, their presence was generally irregular and their abundance normally quite low. Cladocerans were found in very high numbers only in October 1979.

Monthly taxen numbers followed a pattern similar to that at other e

stations. Prior to Generating Station operation, periods of high taxon numbers were slightly more restricted than they were cfter (Figure 2a). Diversity index values followed a pattern similar to taxon numbers. Index values were generally higher for comparable quarters after Station operation began than before (Figure 3).

SV2 and SV5 --

8 Regular, biweekly monitoring of the aquatic macroinvertebrate communities of two sites on the St. Vrain River was initiated in July 1979. All major groups except Coleoptera and Hemiptera had representa-tion at both sites, but SV5 was considerably less speciose than SV2. O Forms comon in the South Platte River were also dominant in the St.

Vrain River. No taxon found in the St. Vrain River was unique to it.

No further analysis is possible because of the brief St. Vrain collec- O tion period of 6 months.

O

O 57 l l

Water Chemistry and Water Temperatures O Analysis of the chemical parameters of the South Platte and St.

Vrain Rivers did not reveal any abnormal or unexpected conditions (Table 8). Monthly water temperature means (am and pm) were calculated for e above and below effluent discharge (Table 9).

Analysis of variance tests revealed significant differences in water temperatures for each month (am and pm, above and below effluent discharge) e among all years (1974-1979) (Table 10). Water temperatures were not sig-nificantly different above and below effluent discharge (am and pm) when Water temperatures were compared for each month, singly (Table 11).

O temperature differences were significantly different among months prior to the initiation of Generating Station operation (June 1974-November 1976) and after power generation began at the Fort St. Vrain Nuclear Generating However, the temperature O Station (December 1976-December 1979) (Table 12).

Some data were often questionable and frequently deemed inaccurate.

obviously-incorrect data could be eliminated, but the remainder could be 3 accepted only with extreme reservation. Much was probably improperly recorded. Thus, analysis of water temperature regimes did not reveal if Generating Station operation (and the associated effluent from Goosequill

1. Pond) had a measurable effect upon the aquatic macroinvertebrate community of the South Platte River.

D D

58 O Table 8. Mean chemical and physical parameters at four stations on the South Platte River, Colorado, 1974-1979.

SP4A-0 SP4A-N SP4U SP48 Cl Air Temp. (C) 13.4 16.6 15.0 15.1 15.3 WaterTemp.(C) 11.0 12.4 11.7 11.8 11.9 g 7.5 7.3 7.2 7.3 7.4 Dissolved 02(mg/1) 13.7 29.1 20.2 18.6 18.4 Dissolved CO2(mg/1) pH 7.9 7.6 7.7 7,8 7.9 g Hardness (mg/l) 339 331 339 338 319 Total Alkalinity (mg/1) 255 395 31 8 301 312 FiltrableSolids(mg/l) 774 498 572 644 647 ,

Dissolved Solids (mg/1) -- 805 785 808 81 5 Conductivity (micromhos/cm) 1272 540 867 928 948 Turbidity (JTU) 31.5 15.8 29.5 22.2 24.7 g 9

O O

O O

Table 9. South Platte River water temperature ('C) recorded by Pubite Service Company of Colorado in the vicinity of fort St. Vrain Nuclear Generating Station. 1974 1979.

JANUARY FEBRUARY MARCH APRIL as pm as pm am pm as pm A* B** A B A B A B A 8 A B A B A 8 Mean v

S; Range N

... ~..........................=_ ......__ -..........................................................._-_-- _ ........... ...

Mean 0.4 2.4 2.3 4.7 , 5.8 8.4 8.2 12.8

0 0.6 0.0 0.3 0.0 0.0 0.0 0.6 2.2 Range 19.4

% 3.9 8.9 6.4 10.0 12.0 13.3 15.0 N 30 29 28 28 30 30 27 26

... -_.....................-- .=- ..___ -- ....._ -- -

_.- _ ...-- - ---=...........................

Mean 2.2 2.1 3.3 2.7 4.3 4.5 6.3 6.7 5.4 6.0 7.8 8.3 9.4 9.3 13.5 13.4 "3

-0.6 0.6 -0.6 0.0 0.6 -0.8 0.6 0.6 0.0 -0.3 1.1 1.1 0.0 1.1 S.6 5.6 Range 18.6 18.6

% 6.4 6.7 8.9 8.6 8.0 8.5 10.0 10.0 12.2 11.9 13.3 13.3 14.4 13.6 us N 31 22 29 22 27 27 26 25 29 29 31 31 30 30 30 30 ua Mean -1.0 -1.0 0.2 -0.3 2.6 2.6 4.8 4.6 4.1 3.8 5.8 5.6 7.3 7.2 10.1 10.1 R -3.3 3.3 3.3 -3.3 0.6 0.6 0.0 0.0 -3.3 -3.3 0.6 0.6 1.1 0.8 2.8 2.8 Range 9.4

% 3.1 3.1 3.3 3.3 5.0 5.0 8.9 7.8 10.0 10.8 10.8 13.3 12.8 16.7 16.7 N 30 30 30 30 28 28 28 28 31 31 31 31 30 30 30 30 Mean 1.4 0.9 1.2 0.9 3.1 2.9 3.1 2.9 8.4 8.1 10.1 9.8 11.9 11.9 12.9 12.9 R 0. 0 0.0 -4.4 -5.0 0.3 0.3 1.1 1.1 0.3 0.3 1.1 1.1 7.2 7.2 7.8 7.8 Range 5.0

% 3.9 2.5 2.8 2.2 5.0 6.7 6.7 17.8 17.8 18.3 18.3 15.8 15.8 17.2 17.8 N 31 31 30 30 28 28 28 28 31 31 30 30 30 30 30 30

.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . = = - - - -_... ......... ............ = -- - -- ............................ ...................

Mean 1.7 1.4 1.9 1.2 4.4 3.9 6.0 5.1 9.1 8.5 11.0 10.3 13.1 12.6 15.3 15.1 R 0.6 0.0 0.6 6.7 1.1 0.6 1.7 6.1 5.0 4.4 5.0 4.4 5.6 5.8 5.6 4.4 Range 17.8 22.2

% 3.9 3.3 4.4 3.9 8.9 9.4 17.2 16.1 12.8 12.5 16.7 15.6 18.9 21.1 N 31 31 31 31 28 23 28 28 31 31 30 30 30 30 28 28

...u...... -_.....................__-- . -

= - . ..........=_ = ................................................

GRAND MEAN 1.0 0.9 1.7 1.1 3.3 3.5 5.0 4.8 6,6 6.6 8.6 8.5 10.0 10.3 12.9 12.9

-1.0 0.9 -1.5 -3.0 0.0 -0.2 0.4 -1.1 0.4 0.2 1.6 1.4 2.9 3.1 4.8 4.6 GRAND RANGE 18.7 4.2 3.9 5.7 5.4 6.7 6.9 10.6 10.1 13.0 12.7 14.5 14.3 15.5 15.0 18.6

• Above effluent discharge.

8elow effluent disciar9e.

Table 9. Continued JUNE JULY AUGUST

MAT am pm am pm as pa as pm A 8 A 8 A 8 A 8 A* B** A 8 A B A B 20.1 24.2 18.1 22.4 Mean 18.8 24.0 16.4 18.9 15.3 17.8 E 15.8 21.1 Range 27.8 24.2 28.3 22.2 26.7

$ 23.3 7 22 26 27 N 10

.. ..........................................................................'t3 20.3 21.3 21.4 24.5 24.5 18.9 18.9 22.5 22.5 Mean 12.9 13.0 12.6 12.7 16.1 16.0 20.3 14.4 18.1 15.1 17.8 17.8 14.4 14.4 17.8 17.8 9.4 9.4 8.9 8.9 11.1 11.7 14.4 N 23.1 23.1 28.3 28.3 g R'"9' 20.6 20.6 16.1 16.7 20.3 20.3 25.0 25.0 26.7 26.7 31.1 79.4 27 28 27 28 29 29 30 30 N 11 11 11 10 25 25 28 28 19.4 19.5 17.8 17.8 22.4 22.3 17.4 17.4 21.7 21.6 Mean 12.5 12.6 16.4 16.3 16.3 16.2 13.1 13.3 13.3 17.8 17.8 12.8 11.7 17.7 16.7 7.2 7.2 10.0 10.0 10.0 10.0 13.1 N Ran9e 22.8 21.1 21.1 25.3 25.8 21.7 21.1 28.3 28.3 20.8 20.8 26.1 25.6

% 16.9 17.2 22.8 31 28 28 31 31 31 31 30 30 25 25 30 30 31 on N 29 29 22.8 22.6 O

18.2 18.2 22.0 21.8 19.5 19.5 22.9 22.7 20.5 20.4 Mean 13.9 13.6 16.6 16.4 12.8 12.8 15.6 15.6 18.3 18.3 16.9 16.9 18.3 17.8 E 8.3 8.3 10.0 10.0 10.0 10.0 27.8 Ran9e 21.1 26.9 26.9 24.2 24.2 27.2 26.1 24.2 24.2 27.8

$ 20.0 19.4 25.6 25.6 21.1 30 27 27 25 25 31 31 30 30 N 31 31 31 31 30 30 30 19.5 19.4 23.0 23.0 24.7 24.7 20.3 20.3 22.0 22.1 Mean 14.0 13.8 14.8 14.6 18.2 18.2 16.1 20.0 20.ft 21.1 21.1 16.9 16.9 15.6 16.7 7.2 6.7 6.7 6.7 14.4 14.4 16.1 R Ran9e 21.1 22.2 22.2 25.6 25.6 25.8 25.8 27.2 27.2 24.2 24.2 27.2 27.2

% 20.6 20.6 21.1 30 30 31 31 30 30 31 31 29 29 N 31 31 29 29 29 29 18.6 20.7 20.4

=...................._..........................

21.1 20.6 18.3 18.2 19.5 19.3 Mean 15.9 14.5 18.4 16.7 18.9 17.6 20.0 4.4 9.4 18.1 17.2 18.3 17.2 8.9 8.9 15.6 15.6 R 7.8 7.8 8.3 8.3 11.7 12.8 22.2 24.4 25.0 Ran9e 25.0 22.5 21.1 24.4 23.9 24.2 23.6 25.6 24.4 22.2

% 23.1 22.8 26.7 31 31 31 30 30 30 30 N 31 31 28 27 29 29 30 29 31 20.9 19.9 20.4 20.4 23.3 23.0 18.9 19.0 21.8 21.6 GRAND MEAN 13.8 13.5 15.8 15.3 17.8 17.2 14.5 16.9 16.8 18.7 18.5 14.2 14.2 17.0 17.1 8.3 8.1 9.1 9.1 12.2 11.1 15.1 GRANO RANGE 25.8 24.5 24.3 28.0 27.3 22.8 22.8 26.8 26.8 19.5 19.4 22.3 22.1 21.7 21.4 25.8

• Above ef fluent dischar9e.

• • Below effluent dischar9e.

1. # # 9 9 e e g g ,

O O O O O Table 9. Continued SEPTEMBER OCTOBER NOVEMBER DECEMBER am pm as pa an pa as pm A* 8** A B A B A 8 A B A 8 A 8 A 8 Hean 15.3 19.2 11.3 14.8 5.6 7.1 1.1 2.5 E 8.9 13.3 6.9 8.3 0.0 1.1 0.6 0.0 g Range 19.2 24.4 15.6 20.6 8.3 12.2 5.3 6.7 N 30 27 29 28 28 28 30 31 Mean 15.4 15.4 18.7 18.7 11.8 12.0 15.2 15.2 5.1 f 6.9 6.6 3.4 3.3 4.8 4.5

<* 11.9 11.9 11.7 11.7 5.3 5.6 7.2 7.2 0.0 00 -0.6 -0.6 0.0 0.0 0.0 0.0

% "*"9' 19.4 19.4 22.8- 23.3 17.2 19.7 20.6 21.1 11,1 11.1 14.4 14.4 6.7 6.7 9.4 9.4 N 28 28 30 30 31 31 30 30 27 26 28. 28 31 31 29 29 Mean 16.3 16.3 18.3 18.0 10.2 10.0 12.8 12.6 5.9 5.7 1.9 7.8 2.4 2.1 3.1 2.9 e 11.0 11.0 12.8 12.8 6.1 4.4 6.0 6.0 0.0 0.0 0.10 0.0 -1.4 1.4 1.1 1.1 9' 24.2 24.2 22.5 22.5 15.0 14.7 19.0 19.0 12.5 11.7 14.4 14.4 6.7 5.0 6.7 6.7 N 28 28 28 28 31 31 29 29 28 28 27 27 30 30 29 29

... .......................... . . . . . . . . . - - -__-............................................................................................. g Mean 15.3 15.4 18.7 18.5 8.4 8.3 10.9 10.8 4.0 3.9 6.3 6.2 2.9 2.8 2.9 2.3 e,

e- 7.2 7.2 13.9 13.9 4.2 3.1 3.9 3.9 0.0 0.0 2.8 2.8 0.0 0.0 0.0 0.0 g Range 21.4 21.4 23.1 23.3 15.6 15.6 17.8 17.8 6.1 6.1 12.2 12.2 6.7 6.1 7.2 7.8 N 30 30 30 30 31 31 30 30 30 30 28 28 31 31 28 28

... ......................................................==_ - - -

Mean 17.1 17.0 19.2 19.1 12.5 12.4 13.4 13.3 5.7 5.6 5.9 6.0 2.1 2. 0 2.1 1.9 m 11.9 11.9 10.6 10.0 8.9 8.9 7.2 7.2 1.7 1.4 2.2 2.2 0.0 0.0 0.0 0.0 Range 4.4 5.0 6.1

% 23.6 23.3 2G.7 26.7 17.5 17.2 18.3 18.3 11.1 11.1 12.2 13.3 4.

N 30 30 28 28 31 31 31 31 30 30 a9 29 31 31 31 31

... .......................................-- - ........................--- == --- ......................._............................

Mean 16.1 16.0 17.1 16.9 11.5 11.3 12.8 12.7 3.8 3.8 5.1 5.1 2.4 2.4 3.3 3.4 m

g 13.1 12.5 13.9 13.3 3.6 3.1 3.9 3.9 -0.3 -0.3 -1.1 -0.6 -1.1 -1.1 -1.1 -1.1

- 9 18.9 19.4 23.3 22.8 15.6 15.6 17.8 16.7 7.5 7.5 10.0 10.0 4.7 4.4 6.1 7.2 N 30 30 29 29 31 31 31 31 31 31 29 29 31 31 30 30

............- =...............- = . . . . . . . . _ . . . . . . . . . . _ . . . . . . . . _ _ _ _ . . - ................................................

GRAND MEAN 15.9 16.0 18.5 18.2 11.0 10.8 13.3 12.9 5.0 4.8 6.5 6.3 2.4 2.5 3.1 3.0 10.7 10.6 12.7 12.5 5.8 5.3 6.1 6.1 0.2 0.2 0.7 0.8 -0.5 -0.5 -0.4 -0.4 GRAND RANGE 6.9 7.3 21.1 21.2 23.9 23.8 16.1 16.4 19.0 18.9 9.4 9.3 12.6 12.8 5.7 5.3

• Above effluent discharge.

" Below effluent discharge.

62 t Table 10. Analysis of variance (A0V) cf water temerature of the South Platte River in the vicinity of the Fort St. Vrain Nuclear Generating Station, Colorado, among the years (19741979) for each month (am and pm, above and below effluent discharge).

H,I F,2 p 3 t

p,j,gg, Q January (am) above effluent discharge, 1975-1979 There is no temp. 18.9899 2.37 res difference among years January (p) above effluent discharge, 1975-1979 13.6242 2.37 Yes January gam) below effluent discharge, 1976-1979 25.4362 2. C Yes January (pm) below effluent discharge, 1976-1979 9.9808 ".68 Yes g; Februa ry am) above effluent discharge, 1975-1979 6.3243 2.37 Yes February pm above effluent discharge, 1975-1979 6.2462  ?.37 ies February am below affluent discharge, 1976-1979

• 5.4141 J.68 Yes February (pm below effluent discharge, 1976-1979 "

7.7794 2.68 fes March (am) above effluent discharge, 1975-1979

• 12.0299 2.37 Yes 9.6184 2.37 Yes March (pm) above effluent discharge, 1975-1979 March tam) below effluent discharge, 1976-1979 "

12.7726 2.68 Yes e March (pm) below effluent discharge, 1976-1979 "

10.87:9 2.68 ves April am) above effluent discharge, 1974-1979 "

17.7985 2.37 Yes April pm) above effluent discharge, 1974-1979 "

7.3807 2.37 Yes April am) below effluent discharge, 1976-1979 "

20.1591 2.68 Yes April (pm) Delow effluent discharge, 1976-1979 "

9.4003 2.68 Yes May(am above affluent discharge, 1975-1979 "

5.2827 2.37 Yes G May pm above effluent discharge, i375-1979 "

4.0189 2.37 Yes May am below effluent dizharge,1970-C79 1.6174 2.37 No May pn below effluent discharge, 1976-1979 "

2.2800 2.37 No June (am above effluent discharge, 1974-1979 5.0874 2.21 Yes June (pm above effluent discharge, 1974-1979 5.3686 2.21 Yes June (am below effluent discharge, 1975-1979 3.7640 2.37 Yes June (pm below effluent discharge, 1975-1979 "

4.7728 2.37 Yes g July am) above effluent discharge, 1974-1979 24.7798 2.21 Yes July pm) above effluent discharge, 1974-1979 12.0614 2.21 Yes July am) below effluent discharge, 1975-1979 "

31.6222 2.37 Yes July (pm) belew effluent discharge, 1975-1979 20.7043 2.37 Yes Auoust (am) above effluent discharge, 1974 '979 11.5165 2.21 Yes August pm) above effluent discharge, 1974-1979 7.0309 2.21 Yes August am) below effluent discharge, 1975-1979 12.4339 2.37 Yes O August pm) below effluent discharge, 1975-1979 9.9568 2.37 Yes September am) above effluent discharge, 1974-1979 2.0894 2.21 No September pm) above effluent discharge, 1974-1979 2.0640 2.21 No September am) below effluent discharge, 1975-1979 "

1.6294 2.37 No September pm) below effluent discharge, 1975-1979 "

2.4929 2.37 Yes 0 teber am) above effluent disenarse, 1974-1979 "

10.5088 2.21 Yes e October pm) above effluent discharge, 1974-1979 6.2252 2.21 Yes Octcber am) below effluent discharge, 1975-1979 11.0476 2.37 Yes October pm) bGlow effluent discharge, 1975-1979 "

6.1350 2.37 Yes November (am) above effluent discharge, 1974-1979 3.364? 2.21 Yes November (pm) abcve effluent discharge, 1974-1979 2.6019 2.21 Yes November (am) below effluent discharge, 1975-1979 2.9652 2.37 Yes November (pm) below effluent discharge, 1975-1979 "

2.4528 2.37 Yes g Cecember am above effluent discharge, 1974-1979 5.5375 2.21 Yes Cecember pm above effluent discharge, 1974-1979 6.7393 2.21 Yes

" Yes December am below effluent discharge, 1975-1979 2.8609 2.37 Cecember (pm) below effluent discharge, 1975-1979 6.6583 2.37 Yes IH

• null hypothesis.

o Fs = calculated F statistic.

Ft = table F statistic.

l l

e!

3 63 Table 11, Analysis of variance (A0V) of above and below effluent discharge water temperatures of j the South Platte River for each month (1975-1979) in the vicinity of the fort St. Vrain )

Nuclear Generating Station Colorado.

p 3

) H,I F,2 t Reject?

June, 1975 (as) Above to Below There is no temperature 0.0697 4.04 ' No difference between above and below effluent discharge June,1975(pm)AbovetoBelow 0.0058 4.02 No

) "

0.0305 4.04 No July, 1975 (am) Above to Below July, 1975 (pm) Atsve to Below 0.0086 4.02 No 0.0019 A.01 No August, 1975 (am) Above to Below "

August,1975 (pm) Above to Below 0.0000 4.01 No September,1975 (ae) Above to Below 0.0058 4.02 No j, 5eptember,1975 (pm) Above to Below 0.0066 4.02 No j October,1975 A% ve to Below C.0405 4.01 No October,1975 Above to Below 0.0016 4.01 No November,1975( ) Above to Below "

0.0026 4.04 No November,1975 ( ) Above to Below "

0.0282 4.04 No December,1975 ( Above to Relow

" 0.0046 4.00 No

] December,1975 ( Above to Below

" 0.2040 4.01 No t '

January,1976 (am) Above to Below O.05 01 4.04 No l January, 1976 (pm) Above to Below 0.8665 4.04 No

! February,19'6 (am) Above to Below

• 0.0710 4.04 No February,1976 (pm) Above to Below 0.0138 4.01 No March,1976 (am) Above to Below "

0.0023 4.00 No March,1976 (pm) Above to Below 0.2022 4.00 No April, 1976 (am) Above to Below "

0.1203 4.01 No April, 1976 (pm) Above to Below 0.0337 4.01 No May, 1976 (am) Above to Below 0.0004 4.01 No 3 May, 1976 (pm) Above to Below 0.0253 4.01 No June,1976(am)AbovetoBelow 0.1226 4.04 No June, 1976 (pm) Above to Below 0.0191 4.01 No July, 1976 (am) Above to Selow 0.0013 4.00 No July,1976 (pm) Above to Below 0.0793 4.02 No August,1976 (am) Above to Below 0.0002 4.00 No j')

August,1976 (pm) Above to Below 0.0440 i

4.00 No l September,1976 (am) Above to Below 0.0057 4.02 No September, 1976 (pm) Above to Below 0.0848 4.02 No October,1976 (am) Above to Below 0.0802 4.00- No October,1976 (pm) Above to Below "

0.0474 4.01 No s.,

M November,1976 (am) Above to Below "

0.0249 4.02 No November, 1976 (pm) Above to Below 0.0098 4.04 No December,1976 am)AbovetoBelow 0.5538 4.01 No December,1976 am) Above to Below 0.2024 4.02 No O

LO

64 + C Table 11. Continued p N'd'Ct?

H F,2 t O

January,1977 (am) Above to Below There is no temperature 0.0330 4.01 No difference between above and below effluent January,1977 (pm) Above to Below 0.0637 4.01 No February. 1977 (am) Above to Belcw 0.0272 4.03 No February,1977 (pm) Above to Below 0.2843 4.03 No $

March,1977 (am) Above to Below 0.1128 4.00 No March,1977 (pm) Above to Below 0.0911 4.00 No April,1977 (am) Above to Below 0.0103 4.01 No April,1977 (pm) Above to Below "

0.0000 4.00 No May,1977 (am) Above to Below "

0.0769 4.00 No g May,1977 (pm) Above to Below 0.0610 4.01 No June,1977 (am) Above to Below "

0.0043 4.03 No June,1977 (pm) Above to Below "

0.0496 4.01 No July,1977 (am) Above to Below 0.0000 4.00 No July, 1977 (pm) Above to Below 0.0894 4.05 No August,1977 (am) Above to Below "

0.0905 4.00 No O

August, 1977 (pm) Above to Below 0.0480 4.01 No September,1977 (am) Above to Below 0.0059 4.01 No September,1977 (pm) Above to Below 0.0513 4.01 No October,1977 m Above to Below "

0.0201 4.00 No October,1977 0.0205 4.01 Above to Below No e

November,1977 (am) Above to Below 0.0995 4.01 No November,1977 (pm) Above to Below 0.0128 4.02 No December,1977 (am) Above to Below "

0.0718 4.00 No December,1977 (pn) Above to Below 0.2169 4.02 No January,1978 (am) Above to Below "

4.9189 4.00 Yes $

January,1978 (pm) Above to Below 0.5584 4.01 No February,19713 (aml Above to Below 0.3879 4.02 No February,1978 (pm, Above to Below 0.2195 4.02 No March,1978 (am) Above to Below 0.0344 4.00 No March,1978 (pm) Above to Below 0.0639 4.01 No April,1978 (am) Above to Below 0.0123 4.01 No April,1978 (pm) Above to Below 0.1327 4.01 No May,1978 (am) Above to Below 0.0815 4.00 No May,1978 (pm) Above to Below 0.0172 4.02 No June, 1978 (am) Above to Below "

0.0102 4.02 No l June,1978 (pm) Above to Below 0.0090 4.01 No g

July,1978 (am) Above to Below 0.0124 4.00 No July,1978 (pm) Above to Below 0.0254 4.01 No O

9

l l

O' 65 Table 11. Continued I 3 Reject?

H F,2 Fg D August, 1978 (as) Above to Below There is no temperature 0.0177 4.00 No difference between above and below effluent

" 0.0167 4.02 No August, 1978 (pm) Above to Below

• 0.0187 4.01 No September,1978 (am) Above to Below " 0.0113 4.02 No q

s September, 1978 (pm) Above to Below

" 0.0255 4.00 No Octobe,,1978 (am) Above to Below " 0.0525 4.00 No October,1978 (pm) Above to Below

• 0.0330 4.01 No November,1978 (am) Above to Below " 0.0130 4.02 , No November,1978 (pm) Above to Below

" 0.1343 4.00 No December,1978 (am) Above to Below O December,1978 (pm) Above to Below

" 0.3037 4.00 No

" 1.7407 4.00 No January,1979 (am) Above to Below " 3.6670 4.00 No January,1979 (pm) Above to Below

" 0.7981 4.02 No February,1979 (am) Above to Below " 0.8543 4.02 No Febru ny, 1979 (pm) Above to Below

} " 0.8076 4.00 No March, 1979 (as) Above to Below " 0.5309 4.01 No March,1979 (pm) Above to Below

" 0.2217 4,01 No r

April,1979 (am) Above to Below " 0.0611 4.02 No l

April, 1979 (pm) Above to Below

! " 2.0702 4.00 No May, 1979 (am) Above to Below "

1.5805 4.03 No d May,1979 (pm) Above to Below

" 2.1788 4.02 No June,1979 (am) Above to Below 4.01 No June,1979 (pm) Above to Below

" 2.3569

" 0.9778 4.00 No July,1979 (am) Above to Below "

1.3280 4.00 No Jaly, 1979 (am) Above to Below

" 0.0207 4.01 No lO August,1979 (am) Above to Below " 0.1547 4.02 No l

August,1979 (pm) Above to Below

! " 0.0243 4. 01 No September,1979 (am) Above to Below 4.02 No 0.0930 l

September,1979 (pm) Above to Below 0.0329 4.00 No October,1979 (am) Above to Below 4.00 No October, 1979 (pm) Above to Below 0.0060 lC November,1979 Above to Below

" 0.0000 4.00 No 0.0036 4.02 No November,1979 Above to Below

" 0.0027 4.00 No December,1979 (am) Above to Below 4.01 No December,1979 (pm) Above to Below

" 0.0238 IH = null hypothesis.

o

.O 2F s= calculated F statistic.

3 able F statistic.

t i F =

t l

O

O-

66

(.

Table 12. Analysis of variance (A0V) of water temperature in the vicinity of the Fort St. Vrain Nuclear Generating Station, Colorado, for each month above and below effluent discharge (am and pm) before Station operation (January 1975-November 1976) and after Station operation (Decemoer 1976-Decembar 1979).

H F,2 7 3

Reject 7 O January, 1975-1976 (am) above effluent discharge There is no temp. 7.4876 4.00 Yes difference between years for the same temp, collection site January, 1975-1976 (pm) above effluent discharge "

3.2631 4.00 No $

Februa ry, 1975-1976 (am) above effluent dischrage "

10.4267 4.00 Yes February, 1975-1976 (pm) above effluent discharge 4.8545 4.00 Yes March,1975-1976 (am) above effluent discharge

• 0.0664 4.00 No March,1975-1976 (pm) above effluent discharge "

0.2038 4.00 No April,1975-1976 (am) above effluent discharge "

1.7187 4.00 No g April,1975-1976 (pm) above effluent discharge "

0.5729 4.00 No May,1975-1976 (am) above effluent Cscharge "

0.0000 4.00 No May,1975-1976 (pm) above effluent discharge "

3.6533 4.00 No June,1974-1976 (am) above effluent discharge "

3.8947 3.15 Yes June,1974-1976 (pm) abcve effluent discharge "

7.3644 3.15 Yes June,1974-1976 (am) below effluent discharge "

0.0550 3.15 No g June,1974-1976 (pm) below effluent discharge "

1.1655 3.15 No July,1974-1976 (am above effluent discharge "

21.4519 3.15 Yes Jely,1974-1976 (pm above effluent discharge "

5.5664 3.15 Yes July, 1975-1976 (am below effluent discharge "

43.6828 3.15 Yes July,1975-1976 (pm) below effluent discharge "

13.7327 3.15 Yes August, 1974-1976 (am) abm t effluent discharge a 4.0375 3.15 Yes August, 1974-1976 (pm) abose effluent discharge

• 1.8280 3.15 No O August, 1975-1976 (am) below effluent discharge "

7.9461 3.15 Yes August, 1975-1976 (pm) telow effluent discharge

• 2.4062 3.15 No September, 1974-1976 am above effluent discharge "

1.3647 3.15 No September, 1974-1976 pm above effluent discharge

• 0.5799 3.15 No September, 1975-1976 a below effluent discharge "

1.8921 3.15 No September, 1975-1976 pm) below effluent discharge "

0.9942 3.15 No O

October, 1974-1976 (am) above effluent discharge "

3.8333 3.15 Yes October, 1974-1976 (pm) above effluent discharge "

3.4883 3.15 Yes October, 1975-1976 (am) below ef fluent discharge "

7.2620 3.5 Yes October, 1975-1976 (pm) below effluent discharge "

7.6086 3.15 Yes November, 1974-1976 (am) above effluent discharge "

0.387 3.15 No November, 1974-1976 (pm) above effluent discharge "

0.5358 3.15 No November, 1975-1976 (am) above effluent discharge "

0.3262 3.15 No g November, 1975-1976 (pm) below effluent discharge "

1.0280 3.15 No December, 1974-1975 (am) above effluent discharge a 20.5839 3.12 Yes December, 1974-1975 (pm) above effluent discharge "

16.7355 3.12 Yes January, 1977-1979 (am above effluent discharge

• 43.1377 3.12 Yes Janua ry, 1977-1979 (pm above effluent discharge "

14.7188 3.12 Yes January, 1977-1979 (am below effluent discharge "

36.2471 3.11 Yes g

Janua ry, 1977-1979 (pm below effluent discharge "

6.3438 3.11 Yes Februa ry, 1977-1979 (am above effluent discharge "

7.2803 3.12 Yes Februa ry, 1977-1979(pm above effluent discharge "

9.0839 3.12 Yes February, 1977-1970(am below effluent discharge "

3.9063 3.13 Yes Februa ry, 1977-1979 (pm) below effluent discharge "

4.3764 3.13 Yes O:

l Ol

y 67 Table 12. Continued p 3 Rehet7 H F,2 t

) March,1977-1979 (am) above effluent discharge There is no temp.

difference between 20.7935 3.11 Yes years for the same temp. collection site

• March,1977-1979 abote effluent discharge 17.0337 3.11 Yes March,1977-1979 below effluent discharge 19.5550 3.11 Yes March,1977-1979 below effluent discharge 14.8039 3.11 Yes b April,1977-1979 m above effluent discharge 28.7645 3.12 Yes April,1977-1979 above effluent discharge 13.7148 3.12 Yes April,1977-1979 below effluent discharge 27.2842 3.12 Yes April,1977-1979 below effluent discharge 12.9279 3.12 Yes May,1977-1979 above effluent discharge "

3.0531 3.11 No l May,1977-1979 above effluent discharge 4.7467 3.12 Yes j' May,1977-1979 below effluent discharge "

0.5588 3.11 No May, 1977-1979 pe) below effluent discharge 2.5603 3.13 No June,1977-1979 am) above effluent discharge 0.7131 3.12 No i June, 1977-1979 above effluent discharge 6.0639 3.12 Yes June, 1977-1979 below effluent discharge 0.4412 3.12 No June, 1977-1979 below effluent discharge "

8.4953 3.12 Yes July, 1977-1979 above effluent discharge 29.3634 3.12 Yes July,1977-1979 above effluent discharge "

26.0263 3.13 Yes

! July,1977-1979 below effluent discharge 29.9934 3.12 Yes July,1977-1979 below effluent discharge "

35.1136 3.13 Yes l August, 1977-1979 above effluent discharge 10.2649 3.11 Yes

! August, 1977-1979 above effluent discharge 14.1640 3.12 Yes l August, 1977-1979 below effluent discharge "

26.7108 3.11 Yes

() August, 1977-1979 below effluent discharge 16.7154 3.12 Yes l Septembar, 1977-1979 (am) above effluent discharge "

2.8545 3.11 No September, 1977-1979 ebove effluent discharge "

3.7462 3.13 Yes September, 1977-1979 belcw effluent discharge "

2.1056 3.12 No September, 1977-1979, below effluent discharge "

3.8262 3.13 Yes October, 1977-1979 am) above effluent discharge ' 16,9197 3.11 Yes October, 1977-1979 pm) above effluent discharge "

4.1161 3.11 Yes

~)

October, 1977-1979 am) below effluent dischargt 19.0860 3.11 Yes October, 1977-1979 pm) below effluent dischargr. "

4.3455 3.11 Yes November, 1977-1979 (am) above effluent discharge 5.5778 3.11 Yes November, 1977-1979 (pm above effluent discharge 1.5040 3.13 No November, 1977-1979(am below effluent discharge "

5.0858 3.11 Tes November, 1977-1979 (pm below effluent discharge 1.4489 3.13 No December, 1976-1979 am) above effluent discharge 1.2488 2.68 No V December, 1976-1979 pm) above effluent discharge "

2.4397 2.68 No l December, 1976-1979 am) below effluent discharge "

1.3239 2.68 No December, 1976-1979 pm) below effluent disc'iarge 3.4498 2.68 Yes I

H null hypothesis.

2F , == calculated F statistic.

j 3 F = table F statistic.

C 0

y C

68 DISCUSSION 9:

Exact delineation of specific effects of Generating Station operation are virtually impossible. Several factors obfuscate an examination of cause and effect relationships, not the least of which is the unreliability 9

of the temperature data for the South Platte River collected by Public Service Company of Colorado. Slight differences between above-effluent readings and below-effluent readings were frequently recorded and were 9

not abnonnal . However, many extreme readings reported seemed improbable (e.g., -3.3 C and lower in winter months, 26.0 C and higher in summer months). The rapidity with which water temperatures often changed in 9

less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> (e.g., a 10.0 C or more change was frequently noted) indicated what was considered to be an unreasonable water temperature variation. Because of such vagaries, the temperature data were treated ,

circumspectly. For example, temperatures at high or low extremes can be immediately detected as faulty, but mid-range values cannot be categorically discounted. For example, a value of 8.0 C in March is not unusual, nor ,

is a value of 4.0 C or 12.0 C. Sometimes only one value was recorded for a scheduled measurement with no indication as to wnether the reading was above or below the effluent discharge. Occasionally, no readings ,

were made for one day or several days in succession. Some greater-than-anticipated differences in temperature were reported between stations above and below effluent discharge when there was no discharge from ,

Goosequill Ditch. These differences were probably because of a lack of unifonnity in selecting temperature-measuring sites. If the inconsistencies 9

9

l 69 in the data are ignored, most differences among the same month of different years may be explained by different meteorological conditions.

The possible unrealiability of the temperature data makes detailed analysis of the effects of temperature changes upon the aquatic macroinvertebrate community largely conjectural. Significant differences among months (am and pm, above and below effluent discharge) and among months before and after initiation of power generation would normally be expected because of varying meteorological conditions. If the discharge from Goosequill Pond altered the thermal regime of the South Platte River, the change should have been detected by comparing water temperatures above and below (am and pm) effluent discharge. However, no significant differences were found. Nevertheless, some discernible changes in the macroinvertebrate community were detected after Station operation began.

J.)

A discussion of observed changes in this community requires recognition of several factors that may qualify the results. Changes in personnel definitely were reflected in the data. However, the length of the study O

tended to average aberrations and diminish the affect of problems that might arise in the final analysis. The level of taxonomic identification masks, to a certain extent, the diversity of the macroinvertebrate communities. For example, Cricotopus is a very speciose genus, and some representatives normally would be expected throughout the year. In contrast, Paralauterborniella has relatively few species and would O

naturally be present for a restricted period. Nor can the fact that some species occur throughout the year be ignored (e.g., Hyalella azteca).

Cycling of populations is certainly a natural phenomenon. Thus, a group

~

abundant one year may be rather rare the next, and q

10. c v

l changes in abundance may be explained by natural cycling. Drift may i account for the repopulation of the area (Hynes 1970).

O Associated with drift population is the constantly-shifting substrate.

Within a station, required (or preferred) habitat components may be lacking (or in short supply) one year but present the next. Import of 9

upstream components (organic and/or inorganic) influences the structure of the comunity (Vannote et al.1980).

The effect of the heated effluent depends largely upon the differ-O ential between the discharge and the ambient water temperature of the South Platte River and the ratio of discharge volume to within-stream volume. Obviously, the season is an important consideration. Associated O

with physical considerations is the category of the invertebrate. El e-vated temperatures may accelerate the development of summer species but retard or stop development of winter species.

O The salient features of the 6-year study are the increased number of macroinvertebrate taxa and greater community diversity of the below-discharge-point stations after initiation of power generation. Annual patterns of community diversity changed markedly after Station operation began. At SP4B, diversity was lowest in the first quarter and greatest in the last, with a steady increase in the intervening quarters. The altered pattern was not so obvious at Cl, but changes did occur. The dilution effect of the St. Vrain River mitigated the affect et de Station's effluent.

O The increase in macroinvertebrate taxon numbers may be explained by either improved identification or an actual increase in number. Both factors may be invoked to explain the change. However, slight temper-ature increases ab)ve normal levels and nutrient introduction may have O O

-n D- 71

' altered the environment to the benefit of previously-marginal or absent 3 forms but not caused sufficient deterioration to preclude typical foms.

Since discharge was intermittent and certainly did not cause severe eutrophication of the South Platte River, it seems reasonable to suppose 3 that slight alterations enabled some forms to successfully invade the area. As unusual fonns were responsible for the increased taxon numbers, this explanation does not seem implausible. Fish species indigenous to O the area were found in fairly constant numbers during the study. Histor-ically, most fonns found in the area were warm-water species. Slight I changes in temperature and nutrient load would typically have little i

L3 effect upon them. The mobility of fishes enhances their ability to escape unfavorable conditions if such should occur. However, more constant and greater effluent discharge may significantly change the g patterns observed to date.

1 I Station operation was more constant in 1978 than 1977 or 1979, and observed changes in macroinvertebrate comunity structure were most O marked in 1978. The relatively low level of plant operation in 1979 was reflected in the diversity indices. Patterns similar to those prior to Station operation were rapidly re-established. It appeared that the g community was able to revert to its pre-operational structure after only a short period of operation.

Interestingly, plotting the cycles of abundance of individual g macroinvertebrate taxa did not generally reveal any altered patterns.

Patterns within one site changed for several forms during the study; but, if the pattern for a particular year was compared to the pattern for that species at other stations, differences were negligible. Only

O l

l b

t-

12 O Polypedilum_ sp. and Chironomus sp. had obviously different patterns at' stations affected by effluent. Such observations support the axiom g concerning the trees and the forest.

Virtually no comparison can be made between the EIS and the data collected from 1974 through 1979. Information on macroinvertebrates in g the EIS is very vague, The data derived from the annual fish collections offered no unexpected results. All forms present were those to be expected in a g-high-plains stream. Most foms mentioned as possible denizens in the area in the EIS were found during the study.

Altered temperature regimes and increased nutrient load were g postulated to be the most probable causes of any detected changes in aquatic macroinvertebrate comunities in the study area. However, the unreliability of the temperature data essentially negates any intelli- ,

gent interpretation of changed temperature patterns and aquatic macroinvertebrate comunity responses. No effort was made to relate nutrient loads to aquatic macroinvertebrate community structure changes. ,

Thus, virtually nothing can be said about whether altered thermal regime or increased nutrient load was responsible for the observed changes in the aquatic macroinvertebrate community. No evaluation of the effect of ,.

the effluent will be possible until the Generating Station operates on a more continuous basis, water temperature is reliably collected, and effects of nutrient introductions are evaluated. 9.

l l

l 91 0

3 73 REFERENCES I 3 American Public Health Association. 1971. Standard methods for the examination of water and wastewater, 13th ed. Amer. Publ. Hlth.

Assoc., Washington, D.C. 874 p.

Brittain, J. E. 1977. The effects of temperature on the egg incubation period of Taeniopteryx nebulosa (Plecoptera). Oikos 29:302-305.

J Carlson, C. A. 1976a. Aquatic invertebrates, pp. 30-37. In. F. A.

Glover, ed., A biological survey of Fort St. Vrain NucTear Generating Site. Thorne Ecological Institute, Boulder, CO.

. 1976b. Fishes, pp. 40-50. In. F. A. Glover, ed., A 3 biological survey of the Fort St. VraiTNuclear Generating Site.

Thorne Ecological Institute, Boulder, CO.

, W. D. Fronk and P. E. Stacey. 1975. Aquatic macroinverte-brate, Fort St. Vrain Ecological Investigations. 1975 Semi-annual Report. Report to Thorne Ecological Institute. 64 p.

, W. Don Frank and S. Cressey. 1974. Aquatic invertebrate monitoring, Fort St. Vrain Ecological Investigations. 1974 Annual Report. Report to Thorne Ecological Institute, Boulder, CO.

. W. D. Fronk, D. L. Propst, R. L. Rohrer and P. E. Stacey.

O 1977. Aquatic invertdrate monitoring, Fort St. Vrain Ecological Investigations. 1977 Annual Report. Report to Thorne Ecological Institute. 38 p.

Corkum, L. D. 1978. The nymphal development of Paraleptophlebia adoptera (McDunnough) and Paraleptophlebia mollis (Eaton) (Ephemeroptera:

9 Leptophlebiidae) and the possible influence of temperature. Can.

J. Zool. 56:1842-1846.

Elliott, J. M. 1978. Effect of temperature on the hatching time of eggs of Ephemerella ignita (Poda) (Ephemeroptera: Ephemerellidae).

Freshw. Biol. 8:51-58.

Galat, D. L. and W. J. McConnell. 1974. A quantitative baseline inven-tory of the aquatic macroinvertebrate and periphyton conununities of the South Platte and St. Vrain Rivers, Fort St. Vrain Nuclear Generating Station. Final Report prepared for Thorne Ecological Institute. Thorne Ecological Institute, Boulder, CO. 188 p.

Hynes, H. B. N. 1970a. The ecology of stream insects. Ann. Rev.

Entomol. 15:25-42.

. 1970b. The ecology of running waters. Univ. Toronto Press, Toronto.

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I 74 Ui Johnson, M. D. 1972. The aquatic biota of St. Vrain Creek and the South Platte River adjacent to the Fort St. Vrain Nuclear Generating Station. M.S. Thesis, Colo. St. Univ., Fort Collins, CO. 151 p. ,

Khoo, S. G. 1968. Experimental studies on diapause in stoneflies. I.

Nymphs of Capnia bifrons (Newman). Proc. Roy. Entomol. Soc. London, Ser. A. 43:40-48.

Knight, A. W. and A. R. Gaufin. 1963. The effect of water flow, temper- ,

ature, and oxygen concentration on the Plecoptera nymph, Acroneuria pacifica Banks. Utah Acad. Proc. 40:175-184.

Lehmkuhl, D. M. 1972. Change in thermal regime as a cause of reduction of benthic fauna downstream of a reservoir. J. Fish. Res. Board Can. 29:1329-1332. ,

Stacey, P. E. 1977. Diversity and heavy metal content of South Platte River invertebrates. M.S. Thesis, Colo. St. Univ. , Fort Collins, C0. ll2pp.

Sweeney, B. W. and R. L. Vannote. 1978. Size variation and the distri-bution of hemimetabolous aquatic insects: Two thermal equilibrium hypotheses. Science 200:444-446. 8 Vannote, R. L. , G. W. Minshall, K. W. Cununins, J. R. Sedell, and C. E.

Cushing. 1980. The river continuum concept. Can. J. Fish. Aquat.

Sci. 37:130-137.

Ward, J. V. 1976. Effects of thermal constancy and seasonal displace- #

ment on comunity structure of stream macroinvertebrates. In.

Thermal Ecology II, G. W. Esch and R. W. McFarlane (eds.), EliDA Symposium Series (CONF-750425), p. 302-307.

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3 75 3

3 ALGAL MONITORING 3

3 J

by Paul gug7,g, 3

O O

i O

s 1

l D

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76.

INTRODUCTION 9 For eight years algal dat:. have been collected from aquatic habitats utilized by the Ft. St. Vrain Nuclear Generating Station. This study has 9

followed the objectives outlined by Public Service Company in the original environmental impact statement (1972). The objectives for algae were the following:

1. To include detailed investigation of algae.

a) Baseline evaluation of important species b) Inventory of algal species c) Effects of effluent on biota, including algae, to be of prime consideration

2. Growth of algae which might be toxic to livestock will be identified.

3. Specific studies of the effects of NALC0 water treatment chemicals will be included in the ecological program.

All of these objectives, except h, have been fulfilled for the algal ,

program. Additional data on algal ecology and possi ble toxin production have also been provided.

The reason for the lack of data for h is obvious. The Generating ,

Station has been operational only for intermittent, limited times during the course of this study. Therefore it is difficult to ascertain what direct environmental impact continual operation of the Generating Station 9

has on the algal component of the biota. Nevertheless, there were some notable alterations in habitat at specific river sites that influenced or changed algal populations.

1. l l

) 77 Predictions for changes in algal composition were also made in the  ;

1

) original impact statement. Many of these predictions were not correct. I

~ Furthermore, from the initial, cursory observations taken in 1971 it is now apparent that different algal groups should have been sampled and

) this was done in subsequent years. However, the macroscopic forms that were identified initially show that some significant changes in algal populations may have taken place.

) This report includes a sumary of findings from the past eight years, a discussion of the validity of initial predictions, possible reasons for observed changes, whether the objectives have been met, and an evaluation

) of the metnodology.

MATERIALS AND METHODS

)

Concrete blocks were set up at seven river sites for sampling peri-phyton, because these are most indicative of local conditions. Monthly collections consisted of scrapings from 25 cm2 areas of the blocks and b adjacent natural substrates such as mud, bricks, etc. Identification and counts were made inmediately following collection, using a Leitz com-pound microscope with phase optics. Counts were taken in a Palmer counting k chamber or a Sedgwick-Rafter counting chamber using a Whipple ocular micro-meter. Actual numbers and living: dead cell ratios were recorded. Photo-graphic verification accompanied all counts and identifications.

) Phytoplankton samples were taken in Goosequill Pond and the rivers by collecting water in one gallon bottles. Direct counts were taken from the water since sedimentation involves a long time period and the counts, thus,

)

78 G might not be representative of the actual sample due to cell death or reproduction. Furthermore,. killing cells for sedimentation interferes #

with determining which algae are living.

Phytoplankton populations are most reliable in Goosequill Pond because periphyton are often eliminated due to lack of light penetration #

because of large numbers of phytoplankton. Periphyton, however, were sampled for qualitative reasons. Conversely, phytoplankton were sampled in the rivers for the same reason. 8 Specific lists and counts were correlated with temperature, pH, turbidity and current velocity. Of these, currents and extremes in temperature were most useful . S' There were four sites that potentially could be affected by Generating Station activities in several ways. Either water removal or discharge would occur at these sites. As a result of water removal or discharge, 4 the six sampling stations were selected to determine the effects of generating activities. The potentially affected sites are Goosequill Pond (GQ), the South Platte River above plant-effluent entrance (SPI) and S below effluent entrance into the river from Goosequill Pond (SP), and St, Vrain River at pumping station (SVI).

CONCLUSIONS AND DISCUSSION #

1. Species Inventory A total of 280 species has been identified during the eight year information gathering period. There were 130 species of diatoms, 91 green 4 algae, 27 blue-green algae, 14 euglenoids, 9 golden-brown algae, four yellow-green algae, two cryptomonads, two dinoflagellates, and one red l 0

\

4

h 79 alga (TableI). Many of the algae are either representative of upstream areas and were carried in by the current, or they did not constitute signi-ficant growths in any population sampled. Most of the algae are pollution tolerant organisms that can adjust to a wide range of temperatures.

Only seven algal species are connon and important in local algal popu-l lations (Table II) and are present in samples throughout most of the year.

l l These algae are the diatoms Navicula cryptocephala, Nitzschia palea and

) Stephanodiscus hantzschii; the green algae, Cladophora glomerata, j Rhizoclonium hieroglyphicum and Scenedesmus quadricauda; and the euglenoid, ,

l Euglena viridis. A description of these algae is provided in Table II.

D

! Distinct algal populations (indicator species) were recorded for all sampling sites. For instance, a diatom, Nitzschia palea was the most i dominant periphyton in the South Platte River, followed by another diatom, P Navicula cryptocephala. While the St. Vrain River also had the same l

l dominants, the order of the two diatoms was often reversed. Furthermore, i

j during the warmer months, large, benthic populations of Cladophora glomerata,,

D a filamentous green alga, grew profusely on any available rock or concrete substrates. On the other hand, during the winter, large populations of Euclena viridis were evident at all sites, although its appearance is delayed one or two months in the St. Vrain River when compared to the South Platte River. Other algae commonly found in certain river sites during late summer included Enteromorpha intestinalis, Rhizoclonium hieroglyphicum and Hydrodictyon reticulatium.

2. River Habitats There are basically three localized habitats in both rivers that sup-port distinctive algal populations--standing water, moving water (current) 0

L 80 Table I. Algal Species List for Aquatic Habitats Near St. Vrain Nuclear Generating Station g Division Bacillariophyta (Diatoms)

Achnanthes conspicua Gomphonema intricatum Achnanthes exigua Gomphonema lanceolatum e Achnanthes inflata Gomphonema parvulum Achnanthes lanceolata Gomphonema subclavatum Achnanthes linearis Gomphonema truncatum Achnanthes minutissima Gyrosigma sp.

Actinella punctata Gyrosigma acuminatum Amphipleura pellucida Gyrosigma attenuatum g Amphiprora ornata Gyrosigma exilis Amphiprora paludosa Gyrosigma macrum Amphora ovalis Gyrosigma obtusatum Amphora pediculus Gyrosigma scalproides Asterionella formosa Hannea arcus Biddulphia laevis Hantzschia amphioxis ,

Brebbissonia sp. Melosira ambigua Caloneis amphisbaena Melosira granulata Caloneis silicula Melosira italica Cocconeis disculus Melosira varians Cocconeis placentula Meridion circulare Cyclotella compta Navicula sp. g Cymatopleura elliptica Navicula acus Cymatopleura solea Navicula capitata Cymbella affinis Navicula cryptocephala Cymbella lanceolatc. Navicula cuspidata Cymbella minuta Navicula exigua Cymbella tumida Navicula graciloides

• Cymbella turgida Navicula iridis Cymbella ventricosa Navicula minima Diatoma elongatum Navicula pupula Diatoma hiemale Navicula pygmaea Diatoma vulgare Navicula radiosa Diploneis elliptica Navicula rhynchocephala Entomoneis ornata Navicula tripunctata #

Epithemia sorex Navicula viridula Eunctia pectinalis Neidium iridis Eunctia vanheurckii Nitzchia acicularis Fragilaria capucina Nitzschia amphibia Fragilaria construens Nitzschia apiculata l Fragilaria crotonensis Nitzschia dubia S Fragilaria vaucheriae Nitzchia fonticola Fragilaria virescens Nitzschia gracilis Gomphoneis erieuse Nitzschia holsatica Gomphonema sp. Nitzschia ignorata Gomphonema acuminatum Nitzschia linearis Gomphonema affine Nitzschia palea G Gomphonema angustatum Nitzschia paleacea Gomphonema constrictum Nitzschia sigmoidea 9

p a p

81 Nitzschia sublinearis Closteriopsis longissima  !

) Nitzschia triblionella Closterium sp.

Nitzschia vermicularis Closterium acerosum Pinnularia sp. Closterium lunula Pinnularia gibba~ Closterium setaceum

-Pinnularia latevittata Coelastrum microporum Pinnularia microstauron Coelastrum sphaericum

) Pinnularia. viridis Cosmarium sp.

Pleurosigma sp. Cosmarium botrydis Pleurosigma delicatulum Cosmarium costatum Pleurosigma elongatum Cosmarium subreniforme Pleurosigma strigosum Crucigenia irregularis Rhizosolenia eriensis Crucigenia quadrata

). Rhizosolenia longiseta' Dactylococcus infusionum Rhoicosphenia curvata Dichotomosiphon sp.

Rhopalodia gibba Dictyosphaerium planktonicum Stauroneis anceps- Dictyosphaerium pulchellum Stauroneis phoenicentron Dimorphococcus lunatus Stephanodiscus hantzschii- Dysmorphococcus sp.

)- Surirella angustata Enteromorpha intestinalis Surirella biseriata Francia ovalis Surirella capronii Gloeocystis botryoides Surirella elegans Gloeocystis gigas Surirella ovalis Gonium pectorale-Surirella ovata Golenkinia radiata

)- Surirella patella Haematococcus lacustris Synedra acus Hyalotheca mucosa Synedra actinoides Hydrodictyon reticulatum Synedra amphicephala Lobomonas rostrata Synedra delicatissima Micractinium pusillum Synedra filiformis Microspora floccosa

) Synedra minuscula Oedogonium sp.

Synedra rumpens Oocystis sp.

Synedra tabulata 00 cystis borgei Synedra ulna 00 cystis lacustris Tabellaria fenestrata Pandorina morum Pediastrum boryanum Division Chlorophyta (Green Algae) Pediastrum duplex k- Pediastrum sculpatum Actinostrum hantzschii Pediastrum simplex Ankistrodesmus convolutus Pediastrum tetras Ankistrodesmus falcatus Phacotus lenticularis Carteria sp. Planktosphaeria gelatinosa Characium ambigua Pleurotaenium sp.

) Chlamydomonas sp. Protosiphon botrydioides Chlorella sp. Pteromonas aculeata Chlorogonium sp. Pteromonas farotidrus Chlorogonium elongatum Pteromonas sinuosa Chlorogonium euchlorum Pyramimonas tetrarhynchos Chlorogonium spirale Rhizoclonium hieroglyphicum

) Chlorococcum sp. Scenedesmus acuminatus Chodatella sp. Scenedesmus armatus Cladophora glomerata Scenedesmus bijuga

O 82 Scenedesmus dimorphus Gloeocapsa sp.

Scenedesmus quadricauda Gomphosphaeria sp.

Selenastrum gracile Lyngbya sp.

Selenastrum lacustris Lyngbya nana Selenastrum westii Lyngbya spirulineides Sorastrum sp. Merismopedia sp.

Spirogyra spp. Merismopedia punctata g

Spondylosium plana Microcystis aeruginosa Staurastrum sp. Nostoc sphaericum Staurastrum chaetoceros Oscillatoria sp.

Staurastrum paradoxum Oscillatoria limnetica Stichococcus bacillaris Oscillatoria limosa Stigeoclonium tenure Oscillatoria minnesotensis Stephanosphaera pluvialis Oscillatoria princeps Tetraedron lunula Phormidium sp.

Tetraspora sp. Phormidium tinctorium Thoracomonas phacotoides Rivularia sp.

Ulothrix sp. Spirulina major Ulothrix subtilissima ,

Ulothrix tenerrima Divisica Euglenophyta (Euglenoids)

Ulothrix zonata Volvulina steinii Astasia sp.

Wislouschiella planktonica Euglena acus Zygnema sp. Euglena caudata Euglena viridis O Division Chrysophyta (Golden-Brown Hyalophacus sp.

Algae) Phacus brevicauda Anthophysa vegetans Phacus helicoides Chrysameba radians Phacus longicauda Dinabrvon sp. Phacus pyrum Dinobryon acuminatum Phacus tortus O Dinobryon campanulostipitatum Peranema sp.

Gonyostomum semen Trachelomonas sp.

Heliapsis mutabilis Trachelomonas gibberosa Synura sp. Trachelomonas hispida S.nura sphagnicola Division Pyrrophyta (Dinoflagellates) g Division Cryptophyta (Cryptomonads)

Ceratium hirundinella Chilomonas sp. Massartia-like sp. (unident.)

Cryptomonas ovata Division Rhodophyta Division Cyanophyta (Blue- een BMogem WhsW sm O an cinalis Division Xanthophyta Anabaena flos-aquae Anabaena limnetica Botrydiopsis sp.

Anacystis nidulana Ophlocytium sp.

Aphanizomenon flos-aquae " $P' Chaemosiphon curvatus e p-Chaemosiphon incrustans Chroococcus so.

9

Table II Description and Occurrence of Common Algal Species Species Description Habitat Cladophora glomerata Course, branched, filamentous green alga. Grows on submerged rocks or other

substrates Euglena viridis Fusiform, unicellular, microscopic alga; Grows encysted on exposed mud or sub-green pigmentation. Euglenoid, changes merged fine silt. Found as extensive shape. green patches along banks of rivers during late winter months.

Navicula cryptocephala Diatom. Golden-brown bilaterally- Grows on mud or submerged areas.

symmetrical unicell. Boat-shaped with Golden-brown patches on surface of sub-round, inflated ends. Motile. Raphe strates. Grows in same areas as (groove) along midline of top and bot- Nitzschia palea.

tom of cell wall. .

w Nitzschia palea Diatom. Narrow Same as Navicula cryptocephala.

Raphe (groove)along , fusiform edgesunicell. of cell wall.

Rhizoclonium hieroglyphicum Unbranched, coarse filamentous green Form free-floating, extensive mats in alga. Goosequill Pond and in stationary waters in the rivers.

Scenedesmus quadricauda Four-celled colony with two spines Planktonic in Goosequill Pond.

eminating from end cells.

1 Stephanodiscus hantzschii Radially symmetrical diatom. Thin Usually planktonic as in Goosequill Pond.

spines along edge of cell walls. Sometimes growing in Cladophora popula-tions.

84 G and riffle areas. The most common habitat involves current over sand or fine silt. These areas support large diatom populations throughcut the 9 year and include euglenoids during late winter months. Most samples were taken from this extensive habitat.

Standing water occurred in backwater areas or behind dams. In addi- O tion to having a diatom flora characteristic of flowing water, these sites fomed large floating mats of the green algae Hydrodictyon, Rhizoclonium, and Spirogyra. Such was the situation at sites SVI, SV and backwater areas 6 at other sites during late summer.

The riffle areas are shallow water areas passing over rocky substrates.

These rocks supported large populations of Cladophora glomerata which in turn g might support epiphytic diatoms such as Diatoma vulgare and Stephanodiscus hautzschii. During the colder months or periods of swift currents only the

- basal portions of Cladophora survived. Quantitative sampling of this alga g was not feasible due to its restricted growth patterns within a given area.

3. Goosequill Pond Goosequill Pond represented an unusual habitat since it was man-made and manipulated more than any river site. Scenedesmus_quadricauda was the dominant alga through most of the year (Fig. 3). In addition, from April O

to October, the filamentous green alga, Rhizoclonium hieroglyphicum, formed extensive floating mats around the edges of Goosequill Pond. Some possible deleterious effects from these algae on other living organisms have been 8

observed and will be discussed later.

9 9

• 85

4. Species Diversity Species diversity was low in all aquatic habitats, indicating polluted conditions. As mentioned in the initial environmental impact statement, the rivers collect large quantities of industrial and municipal wastes and

' dissolved solids before reaching the site. This was reflected not only in low species indices but also the types of dominant algae.

5. Fluctuations and Seasonal Succession in Algal Populations Figures 1-6 represent algal population numbers from 1977-1979. The fluctuations are representative of previous years. As reported previously, the rivers primarily have diatom populations dominated by Nitzschia palea a

and Navicula cryptocephala, although sporadic, temporary increases in other diatom species might occur. These sporadic increases were insignificant during a year's sampling period.

The figures for sites showed that warmer temperatures tended to increase population numbers but these did not show any optimum tempert.ture ranges. The diatoms have a wide tolerance for different conditions. Rather, it appeared to be an interaction between temperatures and current that affected the populations.

The figures also showed a general similarity in population numbers and q

species composition. This indicated that the sites and method of sampling were valid. This was particularly true for 1979 where there was a general decline in algal populations. Even the sites that were not affected by Generating Station activities displayed similar declines. If the Generating Station would have been responsible for this decline at specific sites, the other sampling sites shculd have shown significantly higher population J

q

1 86 T numbers. Furthennore, there were no correlations between Generating Station operation dates and population fluctuations. O Another interesting feature of river populations was the appearance of the euglenoid, Euglena viridis during late winter months (Figs.1, 2, This also was a comon feature of preceding sampling years. G 4-6).

6. Effects of Generating Station on Aquatic Habitats There are four sites that are apparently affected by Generating 9

Station activities: the areas behind the dams in both rivers, which create stationary water environments when the dams are in place; Goosequill Pond which receives Generating Station effluent; and the area downstream O

from the discharge of Goosequill Pond water to the South Platte River, which is affected by Goosequ:ll Pond.

The lake-like conditions behind the dams created areas of debris deposition which provided unfavorable growth conditions for most organisms.

Anaerobic conditions were created causing death of algae and consequently further sedimentation. The sediments might reach several feet in depth.

Other features of this habitat included large growths of large pond or lake algae such as Hydrodictyon, Enteromorpha and Rhizoclonium.

Since Goosequill Pond received effluent from the Generating Station, O

obviously the fluctuations of water levels, nutrients and temperatures were affected by the Generating Station activity. The conditions seemed to favor Scenedesmus quadricauda. However, if the pond remained unfrozen during the winter, a shif t to the diatom, Stephanodiscus hantzschii, took O place.

The site downstream from the entry of Goosequill Pond water into the South Platte River often had significant numbers of algae representative G

O

1. 87 1

of Goosequill Pond. Other river sites did not show this tendency.

7, NALCO Effects While NALCO was identified as a toxicant in the original environmental e impact statement, this did not appear to be the case in laboratory studies on algae, which were conducted in 1973. Under different conditions--axenic, unf algal, autoclaved vs. non-autoclaved NALC0 media--we obtained several results. In axenic non-autoclaved conditions, there was no increased growth 3

of algae. However, using autoclaved NALC0 or NALC0 media in which bacteria had been grown, a significant increase in the test alga Scenedesmus quadri-cauda occurred. The results indicated that NALCO is biodegradeable (by 3

bacteria in our experiments) and heat labile. It also is an organophosphate, thus the phosphates are released upon degradation and utilized by Scenedesmus.

, Using phosphate-free media with autoclaved NALC0 enhanced the growth of Scenedesmus. Therefore the release of NALC0 into aquatic systems could promote the rate of algal growth.

O 8. Toxic Algae Three species of blue-green algae that have been reported to be toxic to livestock were identified during the course of this study. These algae

1. were Anabaena flos-aquae, Aplanizomenon flos-aquae, and Microcystis aeruginosa. However, none of these grew to " bloom" proportions during the past eight years, so there was no danger to livestock.

O Other algae that were not considered toxin producers have recently been determined to produce phytotoxins. For instance, Scenedesmus quadricauda, the dominant alga in Goosequill Pond, Hydrodictyon reticulatum, b

O

88 C and Nitzschia palea release compounds that can affect other organisms in various ways. Scenedesmus, Hydrodictyon, and Nitzschia have been shown g to produce plant toxins that affect growth and development of higher plants.

This could be a factor in stressing plants and reducing plant growth in areas irrigated with water from Goosequill Pond. Knowing that this parameter g.

exists would pemit proper identification of biological vs. Generating Station effects.

9. Comparison of Environmental Impact Statement (1972) With Recent Data The following observations were made prior to 1972:

A. The farm pond (Gooseguill Pond) had a heavy growth of Hydrodictyon 9:'

reticulatum, Oedogonium sp. and Rhizoclonium hieroglyphicum during the 1971 season.

B. Cladophora glomerata (found during all seasons), Stigeoclonium flagelliferum, Olothrix tenuissima and Spirooyra sp. were dominant in the rivers and clogged the riffles of the river when the water level was low.

St. Vrain River was similar to South Platte River. The greatest 8 C.

obvious difference was in the presence of Enteromorpha intestinalis _--

the dominant algal species. This grass-like alga is normally found in saltwater habitats. It grew in the irrigation ditches. No O Enteromorpha was found below confluence of streams.

D. Below confluence of South Platte and St. Vrain, water was swift; attached algae were not as abundant; Chadophora glomerata was 9 dominant. Some diatoms and zooplankton were collected but not identified.

Si l

9

89 E. Salinities of the rivers were high, as evidenced by growth of Enteromorpha intestinalis. The initial samples involved only macroscopically identifiable algae at all sites. For instance, the identified large green algae were slow growing and not i reliable indicators of rapidly changing conditions and were restricted to a few months of growth each year. Rather, the diatom flora, which was mentioned in statement D, should have been 3 sampled since these have been the most reliable indicators of lotic ecosystems. Consequently, the listing of green algae did not provide a good data base for comparison with recent data.

D

10. Comparison of Predictions with Actual Results A. Algae are subject to thermal impact. High temperatures tend to restrict the number of species of periphyton. Each species has

.)

an optimum temperature range.

B. Blue-green algae likely would become the dominant species in irrigation ditches and discharge areas.

O C. The biocide (NALC0 321) is toxic.

D. Blue-green algal toxicity. Anabaena sp. potentially serious problem for livestock.

J As indicated in the previous sections, these predictions did not come true. One component that remained untested was the effect of high tempera-g ture on algal populations. It was predicted in 1972 that excessively warm temperatures (99*F) would cause a drastic shift in algal populations to blue-green algae. Since such temperatures were never reached, this popula-g tion change still remains speculative.

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11. Environmental Trends and Changing Situations 8

The abundance of green algae in the rivers prior to 1972 indicated some changes since that time. The only alga that grew abundantly after 1972 was Cladophora glomerata. Enteromorpha occurred sporadically in If Enteromorpha is an indicator of salinity as stated #

localized areas.

in ?S then the salinities of the rivers have decreased.

Stigeoclonium flagelliferum may have been misidentified since our samples yielded only S_. tenue. Stigeoclonium was never a significant #

component of the river flora.

Goosequill Pond has undJ 'gone a drastic change with regard to Hydro-dictyon reticulatum and Oedogonium sp. Our initial observations in the 4 summers of 1972 and 1973 also indicated large growths of these two algae.

In subsequent years, however, both algae disappeared from Goosequill Pond.

Whether the current dominant, Scenedesmus quadricauda, was present prior 4 to 1972 is not known.

Obviously there have been some changes in these aquatic habitats since 1972 and it might be due to a change in current velocity. As recent data e suggest, Hydrodictyon, Enteromorpha and Rhizoclonium are quiet water algae, therefore the observations prior to 1972 in the rivers may be due to slower currents and lower water levels. g Since 1972 algal populations have not shown much change throughout the years and no changes in dominants have occurred. Fluctuations in populations can be explained by temperature, current, ice formation, water levels and g shifting substrates in the rivers. Goosequill Pond probably is more affected by temperatures, water levels, nutrient availability,and diversion of water. g.

l 1

l 9

1

l

) 91  !

12. Generating Station Effects on Environment There are no direct effects of the Generating Station on the algal flora. As mentioned previously this critical aspect is lacking due to intermittent operation of the Generating Station. Influences other than

~

operation of the Generating Station have been noted in preceding sections.

13. Factors Influencing Environmental Quality There do not appear to be any new factors that influenced algal 3

populations. The stability of the populations over an eight year study indicate that conditions hve remained the same.

, Non-generating station influences include municipal waste discharge, upstream sedimentation, farm drainage, and drastic changes in currents.

All these conditions contribute to a polluted stream. .

3 e

m; I

92 C Figure Legends O

Fig. 1. SVI - St. Vrain Intake Fig. 2. SV - St. Vrain Below Intake Fig. 3. GQ - Goosequill Pond #

Fig. 4. SPI - South Platte Above Intake Fig. 5. SPGQ - South Platte Below Intake Fig. 6. SP - South Platte Below Intake and Discharge from Goosequill Pond 9 Abbreviations used in Figures, e EL - Extremely slow currents ES - Extremely swift currents L - Slow currents

• M - Average current flow S - Swift currents O

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101 Introduction _

Studies of avian populations were conducted at the Fort St. Vrain Nuclear Power Generating Station Site near Platteville, Colorado, from April 8,1972 to December 1,1979. This investigation was part of a 3 multidisciplinary research program to gather baseline information about the biota near the nuclear facility (Ryder 1976).

The goals of thic study were to determine the status of the avian

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population and possible pathways of contaminants through that population in the cottonwood riverbottom ecosystem surrounding the nuclear facility.

Hopefully, data from this study would provide a means to evaluate environ-mental quality in the environs of the facility and contribute to the knowledge of avian populations. Also, if collected after the plant reached full operation, these data would give an indication of the impact 6 of the Fort St. Vrain Nuclear Generating Station on the avian populations.

Objectives s

The objectives of this study were as follows:

s

1. To prepare (or acquire) maps showing the dominant vegetation and surface water to facilitate identification of habitats important to birds at the site; 3

2. To establish procedures for periodic counting of the various species of birds utilizing the site;

3. To prepare, by means of field studies and subsequent analysis g

of the data, annotated lists of the avifauna.

4. To gather infonnation on nesting success of dominant species of birds utilizing the site; D

102 0:

5. Where possible, to gather infortnation on food habits of dominant avian species. Food sources may be pathways for contaminants to the avian population; and

6. To detennine the impact of the Fort St. Vrain Nuclear 8

Generating Station on the indigenous avian populations and their habitats.

S_tudy Areas ,

Bird populations were monitored on three study areas within 3 km of the Nuclear Generating Site which are referred to as St. Vrain River, Goosequill Pond, and South Platte River areas, consisting of 71.6, 8.5 ,

and 52.2 hectares (177, 21 and 129 acres) respectively (Fig.1). See Ryder (1976) for a more detailed description.

Methods 4

Standard avi'n census methods were used with some adaptations (Ryder1976). Data were gathered and analyzed in accordance with the widely-used North American Breeding-Bird Survey (International Bird S Census Comittee 1970) and the Audubon Winter Bird Population Study (Kolb 1965).

Censuses began at sunrise. The St. Vrain River and South Platte 9 River areas were systematically searched by ground reconnaissance aided by 7 X 35 or ~r X 50 binoculars, and the pond was censused with binoculars and a spotting scope, observations being made from the surrounding dike. 3 Birds flying into, from, and contained within the study area were recorded.

Spot maps were kept for territorial males during the breeding season. All nests encountered were marked and revisited to record nesting attempts 3 and success.

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l An intensive search for Red-winged and Yellow-headed Blackbird nests was conducted at Goosequill Pond and a slough and pond complex on 8' the St. Vrain unit.

Censuses were made with varied frequency throughout the year.

Basically, weekly counts were made from May to mid-June and bimonthly 8 counts during spring and fall migrations. Monthly or less frequent counts were made in the winter. All three areas were censused 16 times eacF in 1977,1978 and 1979. Earlier censuses numbered over 20 per year. 8 RESULTS Avian Abundance and Species Composition #

One hundred eighty-seven species (plus 3 subspecies) were encountered during the eight years of study (Appendix A). This is 34 species more than reported in the initial " Biological Survey" (Ryder 1976). S Species present were usually highest in May just prior to nesting, somewhat lower but consistent during nesting, and lowest during winter.

Avian species diversity was calculated using Simpson's formula, e

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. s D=1- (pi)2 i=1 where pi = proportion of sample belonging to ith species, s = number of g j species, and D = index of diversity.

A seasonal pattern was evident for total diversity among the three study areas. In 1972, for example, diversity consistently ranged from e 0.88 through 0.93 with a median of 0.91 for 15 counts from April 25 to August 3 (also see Benson 1973). Other periods showed a lower diversity index (as low as 0.55 in October). Diversity indices in 1979 were not g much different from those in 1972 (Tables 1, 2, 3, and 4).

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105 Table 1. Species Diversity Indices for Goosequill Pond.

9 Dates 1972 1979 l 1st week in May 0.73 0.88 2nd week in May 0.76 0.84 3rd week in May 0.76 0.64 4th week in May 0.83 0.80 1st week in June 0.81 0.56 2nd week in June 0.85 0.64 7

Table 2. Species Diversity Indices for the South Platte River Area Dates 1972 1979 1st week in May 0.89 0.83 2nd week in May 0.89 0.8a J 3rd week in May 0.86 0.83 4th week in May 0.87 0.90 1st week in June 0.90 0.38 2nd week in June 0.91 0.86

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Tables 3. Species Diversity Indices for the St. Vrain River Area J Dates 1972 1979 1st week in May 0.89 0.88 2nd week in May 0.89 0.88 g 3rd week in May 0.92 0.99 4th week in May 0.88 0.89 1st week in June 0.91 0.90 2nd week in June 0.91 0.93 3'

106 L Table 4. Species Diversity Indices for all Three Study Areas Combined Dates 1972 1979 O

lst week in May 0.91 0.90 2nd week in May 0.92 0.91 3rd week in May 0.91 0.91 4th week in May 0.91 0.91 e 1st week in June 0.93 0.90 2nd week in June 0.93 O.91 O

Species diversity indices reflect not only number of species but

" evenness" of individuals within species. Thus, a few species and many of one species would yield a low diversity index. Many species with a O uniform number of individuals for each species would result in a high species diversity. Many ecologists believe comunities with high species diversity are more stable (less sensitive to ecological changes) than 8 comunities with low indices but this concept is being challenged.

Comon Grackles, Red-winged Blackbirds, Yellow-headed Blackbirds and Starlings were difficult to census because they were often sean in #

large flocks, or some of the latter three species were on nests and not visible during the census periods. However, Starlings and Red-winged Blackbirds were abundant permanent residents, and Yellow-headed Blackbirds 9 were abundant on marsh habitats from their first occurrence in spring until departure in fall.

Starlings were usually the most abundant nesting species throughout G tie :tudy and, in general, increased whereas red-wings and yellowheads -

decreased as nesters (see Table 7). Starlings are better adapted to dis-turbed sites, abandoned buildings, and probably to heavy grazing and ei I

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) 107 large numbers of livestock. They coninonly feed around cattle, especially

) following fledging of the young starlings, and in winter are a serious l pest in nearby feedlots. The native blackbirds seem less attracted to grazing cattle although redwings, but not yellowheads, commonly visit feedlots to the west of the Fort St, Vrain Nuclear Generating Site.

l Total individuals and species seen are summarized in Table 5.

Sununer, fall and winter populations have fluctuated widely, and no specific trend is apparent. Spring populations, however, show a fairly distinct pattern of an overall decline in avifauna in 1973 followed by l

a steady recovery to 1977, with declines in 1978 and 1979. The sharp I

3 decline in 1973 can probably be attributed to habitat deterioration due to flooding. The recovery is probably attributable to a natural return to pre-flood conditions. Grazing of livestock was reduced in 1977 but b increased in 1978 and 1979 when a marked decline in redwings and yellow-heads was noted (Table 7).

The non-breeding seasons for all eight years were marked by irregular

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fluctuations of populations, but breeding bird numbers are believed to be j a more sensitive indicator of the state of the habitat. Breeding birds declined during the last two years of the study. Yellow-headed and Red-D winged Blackbirds, particularly, had a very poor breeding season in 1979 with low hatching success. Most other species fared somewhat better.

See Tables 6 and 7.

l The only obvious differences noted in the habitat in 1978 and 1979 l were the reduction in vegetative cover due to grazing, and perhaps lack of runoff water either from irrigation practices or operation of the Fort 3 St. Vrain Nuclear Generationg Station. No data were collected on the

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Table 5. Eight-year tabulation of sp:cits numbers and population levels frca monitoring at the Fcrt St. Vrain Nuclear Generating Station (number of species seen per count followed by total individuals).

Time Period 1972 1973 1974 1975 1976 1977 1978 1979 January No count 19(762) 19(319) 20(335) 10(340) Ho count No count lio count February No count 19(2884) 24(15,474) No count 23(422) 24(478) 30(1121)

March No count 32(709) 25(14,063) 29(709) 33(627) 30(715) 31(546) early April 28(823) 26(326) 32(487) 34(688) 38(720) No count 43(622) 34(498) late April 50(871) 34(561) 37(441) 44(719) 46(903) 40(717) 1st wk liay 47(574) 33(381) 45(534) 45(591) 48(729) Ho counL U 37(488) 2nd wk May 47(583) 39(382) 62(833) 52(533) 47(777) 50(640) 54(510) 3rd wk May 48(593) 45(543) 43(563) 55(728) 54(855) 43(522) 38(397) 4th wk May 48(691) 38(450) 46(523) 50(635) 49(656) 45(565) 44(451) lst wk June 35(500) 39(373) 40(641) 42(491) 38(569) 49(614) 43(518) 40(426) 2nd wk June 41(558) 33(414) 42(583) 40(419) 42(513) 46(660) 42(450) 40(416) 3rd wk June 38(551) 38(426) 33(469) 34(340) 39(585) 44(635) 40(457) 43(536) 4th wk June 37(509) 32(324) 34(426) 37(373) 110 count 40(589) 41(510) 37(378) 1st wk July 36(704) 33(421) 32(537) 32(483) 38(731) No count 40(560) No count 2nd wk July 37(681) 29(433) 34(541) 36(522) flo cnunt No count No count No count 3rd wk July 36(680) 34(437) 37(478) No count 41(600) 38(534) 37(50M 29(409) 4th wk July 37(588) 30(779) 36(550) 40(1145) No count No count No count O e e e e e e o e e e

Table 5, continued.

Time Period 1972 1973 1974 1975 1976 1977 1978 1919 lst wk August 37(658) 28(838) lio count 110 count 110 count No count tio count 38(750) 2nd wk August 38(851) 34(1123) 40(386) No count No count 34(571) No count 3rd wk August 42(757) 33(997) 35(565) 46(685) 37(2289) No count 140 count 36(377) 4th wk August No count No count No count No count No count No count 37(1299).

1st wk September 43(1080) 36(1287) 40(879) No count 140 count No count No count 38(897) 2nd wk September No count No count No count 43(1917) No count 110 count No count 3rd wk September 45(605) 43(879) 47(2392) No count 37(1046) 4I(980) 33(468) 31(1008) 4th wk September llo count 39(963) No count ilo count No count No count No count Oc tober 36(1190) 29(?402) 29(532) 31(442) 46(596) 34(856) 30(1692) 25(1737) 8-November 32(1642) 23(455) 23(2057) 27(387) 33(580) 26(45ti) 26(565) No count December 23(611) 22(283) No count No count No count lio count No count 22(192)

Hay 1973 counts probably not comparable to those in 1972 and 1974. Due to floods, it was not possible to complete counts of all 3 areas weekly in May 1973.

Early May count in 1978 delayed by unusually late snowstorm.

7-110 C Table 6. Sumary of the 1979 intensive nest search on the St. Vrain Study Area and Goosequill Pond.

Total Percent Percent Percent 8'

Area and Species Nests Successfull/ Unsuccessful unknowa h.VrainStudyArea American Bittern 2 0.0 100.0 0.0 Yellow-headed Blackbird 6 0.0 83.3 16.7

• Red-winged Blackbird 22 4.5 77.3 15.2 Mourning Dove 3 0.0 66.7 33.3 Gooseguill Pond Yellow-headed Blackbird 3 0.0 0.0 100.0 Red-winged Blackbird 3 0.0 0.0 100.0 MEggs to fledglings.

9 Table 7. Total nestings of Red-winged and Yellow-headed Blackbirds at the Fort St. Vrain Nuclear Generating Station, 1972-1979.

Number of Nests Followed Species 1972 19731/ 1974 1975 1976 1977 1978 19790 Red-winged Blackbird 27 25 27 16 26 68 23 25 Yellow-headed Blackbird 54 20 31 56 53 100 33 9 8 MoosequillPondwas drained in May 1973 and May 1979.

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4 111 avian census project regarding water levels nor changes in water flow.

O Cattle numbers were recorded on all plots during each bird count.

Environmental disturbances increased throughout the study, particu-larly in 1979. Rather heavy grazing of the areas was seen in early O

spring and late summer. Goosequill Pond was drained in May of 1973 and 1979 "ir, an effort to control muskrat and beaver activity in the peripheral dike." The low water level of the pond favored migrants but q

not nesting birds. Waterbirds were able to feed there most of the winters and many of the falls. Waterfowl hunting probably affected local wood duck production in the South Platte area. Irrigation in the adjacent field caused pronounced fluctuations in the water levels of the beaver ponds throughout the summer. Efforts were made during at least two summers to poison prairie dogs. Prairie dog numbers, however, usually recovered by fall, so it is believed the prey base they provide for raptors such as Great Horned Owls was not seriously altered.

Food Habits of Birds g

A special study of the contents of regurgitated pellets of Great Horned Owls was conducted, as they were the dominant year-round bird of prey on the areas and a study of their food habits might indicate possible pathways of contamination. No other food habits data were collected as it would have involved killing birds which would have altered census data.

The results of the Great Horned Owl will be the topic of a special report to be developed. But, it is important to note 8 species of resident mammals, 4 resident bird species as well as carp, crayfish, J

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t 112 and insects were eaten. The invertebrates, particularly, might be the logical pathways of contaminants through the ecosystem. If abnormal levels of contaminants were reported in any of the small mamals, bio-magnification could occur in the foods of owls. Production of young owls was remarkably consistent (2 to 3 young each year) so no immediate adverse effect of the Fort St. Vrain Nuclear Generating Station is suspected at this point.

Our study indicates that contrary to their primarily nocturnal habits, the Great Horned Owls fed to a large degree on the diurnal black-tailed prairie dog (21.2% biomass). Perhaps future consideration employing poisoning to control prairie dogs should recognize that Great Horned Owls are helping control these rodents and that there may be a danger of poisoning non-target species.

9

SUMMARY

Eight years of repeated censuses of birds indicate that avian species diversity has remained rather constant but that total numbers of individ- 8 uals (especially nesters) has been declining the past 2 years from a peak in 1977. Similar declines in nesting Red-winged Blackbirus were reported in the Dakotas by U.S. Fish and Wildlife Service biologists (J. F. Besser, 8 person 1 com.). Also, reductions were noted in Yellow-headed Blackbird nesting populations in 1978, and to a lesser extent in 1979, in an inten-sive study of a large marsh approximately 13 miles east (Ryder, unpub- 9 lished data). There drawdown, burning, and hailstorms seem responsible.

Declines on Goosequill Pond were, no doubt, largely due to drawdown 9

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O 113 during the territory-establishment phase o/ nesting. Continued heavy S grazing of the St. Vrain River study area is considered more detrimental to nesting birds than observed effects of the Nuclear Generating Station operation so far.

9 LITERATURE CITED Benson, D. E. 1973. Avian monitoring at the Fort St. Vrain Nuclear D Power Site in Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 71pp.

International Bird Census Comittee. 1970. An international standard e for a mapping method in bird census work, Audubon Field Notes 24:

722-726.

Kolb, H. 1965. The Audubon winter bird-population study. Audubon Field 3 Notes 19:432-434.

Ryder, R. A. 1976. Birds. pp. 120-129 In. A biological survey of Fort St. Vrain Nuclear Generating Station Site. Thorne Ecol. Inst.,

3 Boulder, Colo. 138pp.

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114 APPENDIX A. Additions to Checklist of Birds of the Fort St. Vrain Nuclear Generating Site (Ryder 1976). ,

Species Status Common Loon (Gavia immer) M, r Horned Grebe (Podiceps auritus) M, u e Double-crested Comorant (Phalacrocorax auritus) R, c Green Heron (Butorides striatus) M, r Snowy Egret (Egretta thula) M, u e Common Goldeneye (Bucephala clanoula) M, u Hooded Merganser (Lophodytes cucullatus) M, r Sandhill Crane (Grus canadensis) M, r e Semipalmated Plover (Charadrius semipalmatus) M, r Black-bellied Plover (Pluvialis squatarola) M, r Willet (Catootrophorus semipalmatus) M, u g Pectoral Sandpiper (Calidris melanotos) M, u Baird's Sandpiper (Calidris bairdii) M, u Common Tern (Sterna hirundo) M, r g Black Tern (Chlidonias niger _) M, u Burrowing Owl (_Athene cunicularia) S,u Poor-will (Phalaenoptilus nuttallii) S, r Tree Swallow (Iridoprocne bicolor) M, u Long-billed Marsh Wren (Cistothorus p. 'ensis) S, u Bewick's Wren (Thryomanes bewickii) M, r Veery (Catharus fuscescens) M, r Townsend's Solitaire (Myadestes townsendi) W, u Blue-gray Gnatcatcher (Polioptila caerulea) M, r O

Golden-crowned Kinglet (Regulus satrapa) W, r e

) 115 l APPENDIX A, continued.

Species Status Philadelphia Vireo (Vireo philadelphicus) M. r Warbling Vireo (Vireo gilvus) S. u l

Tennessee Warbler (Vermivora peregrina) Mr l

BlackpollWarbler(Dendroicastriata) M, u l

Yellow-breasted Chat (Icteria virens) S, c

) American Redstart (Setophaga ruticilla) M, u Orchard Oriole (Icterus spurius) M, r House Finch (Carpodacus mexicanus) R, u 3

Lesser Goldfinch (Carduelis psaltria) S, r White-throated Sparrow (Zonotrichia albicollis) W, u 3

• R - Resident a - abundant i

M - Migrant c - common W - Winter Resident u - uncommon S - Summer Resident r - rare D

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INTRODUCTION O

The vegetation adjacent to the St. Vrain Nuclear Power Generating Station was investigated from 1972-1979. The purpose of these investigations was to inventory and classify the vegetation, and to test for directional change in the vegetation as a result of changing O environmental parameters, especially those caused by the Generating Statien.

Early efforts focused on vegetation inventory and classification; O from this work seven general categories of vegetation were recognized:

1.) Cottonwood 5.) Native pasture 2.) Willow carr 6.) Irrigated and seeded g 3.1 Cattail-sedge pasture 4.) Abandoned cropland ,.) Roadsides and fencelines Specific information on these types can be found in the 1972 and 1973 reports as well as the Biological Survey report of 1976.

If the vegetation samples taken during the inventory period are grouped according to dominant and sub-dominant species the following O

classification emerges:

I. Undisturbed Lands (or, more specifically, less disturbed)

A. Short-grass prairie with shrubs B. Mid-grass prairie g C. Saltgrass communities D. Moist to wet communities II. Disturbed Lands A. Extremely disturbed weedy communities O

B. Pastures and fields C. Modified short-grass prairie D. Modified mid-grass prairie These groupings are very general and have a high degree of inter- g gradation.

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O 119 Western wheatgrass (Agropyron smithii) was the species with

, greatest mean ground cover at the time tne initial inventory was made in 1972. It was followed in importance by saltgrass (Distichlis stricta),

and, at a considerably lesser cover value, cheatgrass (Bromus tectorum).

g The relative importance of cheatgrass is a strong indication of a dis-turbed environment. The ten most abundant species of the St. Vrain Nuclear Power Generating Station area at the time of the 1972 inventory are given in Table 1.

The vegetation of the St. Vrain area is fairly typical of that for the region; human land use practices such as farming, livestock grazing, and irrigation have had a marked impact on the structure and composition of the vegetation. In order to separate possible effects that the St. Vrain Station might have on the vegatation from other effects of human and animal disturbance, exclosures were placed in the primary vegetation types found around the plant. These exclosures were used to measure vegetation cover, which is defined as the area of land surface upon which the shoot biomass is projected, J 2 and production (oven dry grams /M ) of aboveground plant material.

Th'ese quantities from inside the exclosures were compared with values of tne same variables taken from outside, and adjacent to, the exclos-o ures. The location and names of the exclosures are shown in Figure 1.

Ten exclosures were placed at the beginning of the research period; two were temporary and used only in the early phase of the investigation 3 to measure the characteristics of the cattial-sedge and willow carr comuni ties. These results have been discussed in earlier reports.

Of the remaining eight exclosures, one was destroyed during the course of investigation. One study area, the St. Vrain River Loop, was not l

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TABLE 1.

Mean cover, standard error, and range for the ten most important herbaceous species encountered in the inventory sample.

O Species Mean S.E. Range Agropyron smithii 5.1 7.1 31.0 0 Distichlis stricta 4.1 9.4 30.0 Bromus tectorum 2.6 6.5 40.0 Poa pmtensis 2.5 5.7 29.0 0 Equisetwn kansanum 1.6 10.2 70.0 Kochia scoparia 1.6 4.8 26.0 Sporobolus cryptandrus 1.3 2.0 10.0 e Andropogon gerardi 1.0 5.4 36.0 Tara.mca officinale 1.0 1.9 8.0 Bromus ir., . -is 0.9 4.0 26.0 g O

9; O1 0

121 l

l KEY 70 SYMBOLS:

l- Xj =. Confluence Exclosure X = Irrigated Pasture Exclosure 2

x, . cooseou m Exciosure X4 = St. Vrain River Loop j X$ = Cooling Towers Exclosure j X6 = Ben Houston Exclosure f

\

X7 = South Platte River Exclosure Bj = W1110w Carr Exclosure (ternporary)

I 82 = Cattall-Sedge Exclosure (temporary) s Defunct pennanent exclosure site 3

O Xi I

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) rana.eiur

-)82 X. Xs  !

a cooling towers g

Y ]powerplant 8.

O X.

Xr

~

M L.

o Figure 1. Line drawing of the Fort St. Vrain Nuclear Generating Station study area.

3 r

l

122 '

really an exclosure, but was an area naturally isolated by the St.

Vrain River on one side and property boundaries on the other. This O

area was treated as an exclosure because of its separation from the rest of the comunities and the human arid livestock impact on them.

The six remaining exclosures were periodically subjected to O

stress during the course of investigation. All exclosures except the Cooling Tower and Irrigated pasture were flooded in May and June of 1973. Livestock broke into some of the exclosures early in the course 9

of the investigations as well. Because of such problems, all exclosures were re-fenced and re-established during late 1973 and early 1974. Results given in this report are based on information collected since spring of 1974.

METHODS Fifteen plots 20 x 50 cm in size (0.1 M 2) were systematically placed on a 3 x 5 grid within each exclosure to sample herbaceous production. Fifteen 0.1 M2samples were also taken outside of and adjacent to the exclosure. Each of the plots were clipped in

• August of each monitoring year to estimate standing crop. This estimate was made by species or by growth-form. Clippings were all converted to an oven-dried basis. Results are presented as O total production by g/M .2 Data from 1977-1979 were analyzed using discriminant function analysis to test for significant differences between inside and outside the exclosures. O 2

Vegetation cover was measured by twenty-five 20 x 50 cm (0.1 M )

plots placed on a 5 x 5 grid within the exclosures. Vegetation cover outside the exclosure was measured using the same number O O

123 of plots systematically placed at 2 M apart at a 10 M distance from the exclosure. Cover was estimated using cover classes:

1 = 0-5% 4 = 51-75%

2 = 6-25% 5 = 76-95%

3 = 26-50% 6 = 96-100%

D and results were tabulated using the mean value of the class (i.e. 2.5%

for cover class 1) as the numerical value reported for cover. Cover sampling was conducted in June and August of each year. Results Lere D reported by summing mean species response into the following categories:

I Perennial Native Graminoids Perennial Introduced Grasses (including those used

forseeding)

Perennial Native Forbs Perennial Introduced Forbs l Annual Native Grasses Annual Introduced Grasses Annual Native Farbs Annual Introduced Forbs Shrubs Total 3 This grouping was done in order to facilitate recognition of change in community structure as a function of plant growth-form. A differ-ence value was calculated by subtretcting the sum for each category 9 for each year outside the exclosure from the sum for each category for each year inside the exclosure. This difference value is pre-sented in bar graphs.

RESULTS AND DISCUSSION A number of factors influenced the vegetation results reported here. One problem with any long-term study is the turnover of field and laboratory personnel. Another confounding factor is environmental

( variability, which can easily mask, over short periods of time (up to fifty years), any significant changes that the vegetation might be undergoing. Environmental oscillations are reflected in the production b

l 124 and cover values, as well as the relative importance, of vegetation species and growth-forms. The influence of these factors cannot O

be easily identified, but must be considered to have an effect on the variability and error levels of the data.

The use of exclosures presents problems of another nature. Often, 9

especially on the plains where wind is an important environmental factor, the fences themselves act as catchments for many weedy species as they are dispersed across the landscape. This, in conjunction O

with the moisture that may possibly be present as a result of a

" snow-fence" effect, can bias the apparent response of the vegetation to release from grazing pressure. In addition, when cover classes are O

used to estimate vegetation cover (a technique that is used to minimize differential estimator abilities), it is necessary for a species or growth-form to show at least a 12.5% change in cover before O

any effects become apparent. Results presented in this section were interpreted with these factors in mind.

Production, O

Table 2 gives total production values during the monitor years of 1977-1979 for all exclosure sites and the St. Vrain River Loop.

The most pro /uctive exclosure was the irrigated pasture; this is not surprising in light of the supplemental watering it received. Ben Houston Exclosure, located in a seeded pasture, also showed greater productivity than most sites. The remaining exclosures, and the St. Vrain Loop, showed similar production values.

• Table 3 shows the result of discriminant analysis on production data for 1977-1979. The variables used to make the discriminations are given in column 2 of that table. Once, again, the Irrigated O l

• l \

[) 125 l

[) TABLE 2.

2 Total production values for exclosures in grams / meter for the'three monitor years.

)

1977 1978 1979 Exclosure in out in out in out Confluence 67.5 36.3 84.1 80.0 172.8 169.6 Irrigated Pasture 525.7 209.7 277.8 165.3 312.3 285.1

[) Goosequill 62.5 51.1 62.2 68.4 108.7 160.1 Cooling Tower 147.3 103.5 72.4 92.6 82.0 56.4 Ben Houston- 462.3 270.2 511.2 48.9 336.6 16i.0 D South Platte 292.9 59.5 152.1 104.4 162.6 180.4 St. Vrain Loop 333.4

• 183.0

• 72.7

• 3

• value not taken O

l O

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l

126 Table 3.

Discriminant Analysis using two variables to show differences between inside and outside the exclosures.

Exclosure Variables Used Year Significance #

Confluence 3romus tectorum/ 1977 -

5. japonicus 39,g _

Sympn, oncarpos occidentalis 1979 -

O Irrigated Pasture Bromus inermis 1977 .01

?196#""* # ##'"#"*

1978 .01 1979 .01 O

Goosequill Bromus tector:c:/ 1977 .05

3. japonicus 39,g _

Sporobolus cryptandrus 1979 .05 Cooling Tower Ambrosia coronopifolia 1977 -

O 3porobotus cryptandrus 39,g .93 1979 -

South Platte Rhus radicans 1977 .01

1. 9"E ##P#8 1978 8 occidentalis -

1979 -

Ben Houston Agrapyron elongatum 1977 .01 Matichtis atnata 1978 .01 1979 .01 O

l l

i Ol i

.O

3 127 Pasture and Ben Houston exclosures were prominent; in this case because of consistently significant differences between inside and out. These differences may confidently be ascribed to grazing practices. The South Platte River exclosure shows significant difference in 1977 based on shrub production. The Goosequill exclosure shows signifi-cant differences in 1977 and 1979 based primarily on differences in annual grass production.

Cover D

St. Vrain Loop. Although not an exclosure, this area is of interest because it was not much influenced by humans or livestock.

I It is, however, subject to periodic flooding, which has a disturbing effect on the vegetation. Recovery from flooding is somewhat evident in the increasing total cover values (most evident in the graph of June cover values) from 1974 to 1979 (Figure 2). Native perennial 9 grasses and introduced perennial forbs dominated this location, with l

i a seasonal peak of annual grass cover in June.

Confluence Exclosure. T* shrub category best illustrates the g

E trend effected by release of 'ng pressure on the vegetation of this exclosure. With the except of 1978, there is a general upward climb of shrub cover within the exclosure compared to cover

~'

values outside the exclosure. This is reflected by the positive difference values shown for shrubs in Figure 3. Weedy perennial

, forbs clearly seemed to do better inside the exclosure than outside 3 it. A slight trend toward an increase of perennial native grasses and graminoids within the exclosure could be shown in the August

! graph; this should certainly not be taken as strong evidence for 3 directional 9ange.

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Figure 2. Percent of ground covered for St. Vrain River Loop sanip'a. ABBuvlATIONS:

Each bar within each group represents a year in the following IGN: Perennial Native Grass or Graminoid WY JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 PGl: Perennial Introduced Grass AUGUST: 1975 - 1976 - 1977 - 1979 PFN: Perennial Native Forb PFI: Perennial Introduced Forb ABI: Annual Introduced Grass O O O O O O O O O O O

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PGN: Perennial Native Grass or Graminoid PGI: Perennial Introduced Grass

.w ,, Pfff: Perennial Native forb PFI: Perennial Introduced forb AGI: Annual Introduced Grass Figure 3. Difference values for Confluence Exclosure. Each bar within ^ ^"""* '" "'*

each group represents a year in the following way:

JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979

130 g o

Irrigated Pasture Exclosure. It is verj clear from looking at the negative difference values that the vegetation outside this exclosure is dominated by introduced perennial grasses (Figure 4), especially meadow g fescue (Festuca elatior). Diversity appears to be higher inside the exclosure, as shown by the greater number of positive difference values for categories other than perennial native grasses. Perennial native forbs g were uniformly more abundant inside the exclosure. A trend toward increasing cover within the exclosure can be seen by looking at total difference values in August when the early flush of perennial introduced grasses due to g irrigation has been moderated.

Goosequill Exclosure. No easily interpretable information can be drawn from this exclosure. Differences in cover between inside and out are g more marked in June than August; perennial introduced grasses and annual introduced grasses seem to dominate the exclosure (Figure 5). This could be attributed to the effects of the exclosure itself, as mentioned earlier. g Cooling Tower Exclosure. The data from this exclosure are incon-clusive. The ambiguity of the results are perhaps due to the proximity of this exclosure to construction activity and heavy grazing. The June and g August results seem contradictory (Figure 6).

Ben Houston Exclosure. The high negative difference value (Figure 7) for perennial native grasses nay be due to western wheatgrass, which is ,

being called a native grass, in a pasture seed mix. Another possibility is that saltgrass, an unpalatable range grass, had a high cover outside the exclosure because of reduced competitive pressure from other, more heavily 9

grazed, species. Competition within the exclosure would keep the cover of this species and consequently the perennial native grass growth-form low. In general, no conclusions about the effect of the exclosure can O

confidently be made.

O

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PGN: Perennial Native Grass L_ , J l=- PGI: Perennial Introduced Grass PIN: Perennial Native Forb PFI: Perennial Introduced Forb Figure 4. Difference values for Irrigated Pasture Exclosure. Each Art: Annual Introduced Forb bar within each group represents a year in the following

"^Y JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979

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PGN: Perennial Native Grass

-24 PGI: Perennial Introduced Grass

PFN: Perennial Native Forb PFl: Perennial Introduced Forb AGI: Annual Introduced Grass AFI: Annual Introduced Forb Figure 5. Difference values for Goosequill Exclosure. Each bar within each group represents a year in the following way:

JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979 0 e e e e e o _ - - - _ .

e _ _ _ - _ - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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la ABBREVIATIONS:

PGN: Perennial Native Grass

( .,,

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- 2* PGI: Perennial Introduced Grass PIN: Perennial Native Forb

= PFI: Perennial Introduced Forb AGI: Annual Introduced Grass AFI: Annual Introduced Forb Figure 6. Difference values for Cooling Tower Exclosure. Each bar within each group represents a year in the following way:

JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979 l

e. .

Ltn istLlut listirJat and tuvia veins 86 g g liar,ka isit1234 auws sowie emins ll

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. is ABBREVIATIONS:

.. PGN: Perennial Native Grass PGI: Perennial Introduced Grass figure 7. Difference values for Ben llouston Exclosure. Each bar PFI: Perennial Introduced forb within each group represents a year in the followin9 AFI: Annual Introduced f ort "dY JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979 O e e 4 e e e e e e e

l

) 135 j l

South Platte River Exclosure. This exclosure is similar to I the Confluence exclosure in that directional change in vegetation as a response to reduced grazing pressure is evident in the positive  ;

difference values for shrubs (Figure 8). For some reason, the cover inside the exclosure in August was uniformly lower than that outside l the exclosure. It may be that increased cover of shrubs leads to a l

l more severe competitive situation for the grasses and forbs, a l

l situation that would be more evident at the end of the growing season

) (August) than at the beginning (June) when resources such as water would not be so limiting.

CONCLUSIONS AND INTERPRETATION From the information generated, it can be concluded that, to date, the St. Vrain Nuclear Power Generating Station has had little, if any, influence on the vegetation communities adjacent to it.

This is excepting, of course, direct disturbance that is a function of construction activity.

l Some indication of a trend toward increasing cover as a result of release from livestock grazing pressure is evidenced by the increase

in production values for some of the exclosures over their adjacent outside areas. This is somewhat corroborated by the increase of I

l shrub cover within the Confluence and South Platter River exclosures.

However, long-term changes, such as an increase in importance of D perennial native grasses within the exclosure, are not yet evident.

l l As mentioned earlier, the exclosure itself may play such a role l in modifying the environment that response to reduced grazing pressure D may be confounded. The only solutions to this problem would be to .

1 i

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E ABBREVIATIONS:

t -- r _a W ,,

PGN: Perennial Native Grass

• PGI: Perennial Introduced Gras PFN: Perennial Native Forb Figure 8. Difference values for South Platte River Exclosure. PFI: Perennial Introduced forb Each bar within each group represents a year in the AGI: Annual Introduced Grass following way:

JUNE: 1974 - 1975 - 1976 - 1977 - 1978 - 1979 AUGUST: 1975 - 1976 - 1977 - 1979

II 3 137 increase the size of the exclosures or prohibit grazing over a large O )

portion of the study area. Even so, significant changes might not l

become evident for many years.

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1 l 138 0:

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O EC0 PHYSIOLOGICAL CHARACTERISTICS O'

O.

O by M. J. Trlica O

O O

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O 139 INTRODUCTION Terrestrial vegetation surrounding the St. Vrain Nuclear Generating Station may be directly or indirectly affected by the plant's operation.

Operation of the Generating Station will probably result in releases of a

small amounts of radionuclides. Heat, water vapor, and salts will also be lost to the atmosphere as a result of cooling tower operation. In addition, water effluents will be released from the station which could O affect vegetation along the water courses, or this water might be used for irrigation.

The environmental impact statement relating to the operation of the O St. Vrain Nuclear Generating Statien indicated that approximately 2300 gpm of water would be lost from the cooling towers as a result of evaporation and drift. Of course, the actual amount of evaporation and O drift would be dependent upon atmospheric conditions including wind speed and direction, atmospheric stability, air and water temperatures, ambient humidity, and Station power level. Since make-up water for these towers comes primarily

O from the polluted South Platte and St. Vrain Rivers, concentrations of salts and other toxic chemicals could be expected to be high. These chemicals enter the rivers as a result of geological processes and because O of industrial and fanning activities up tream from the Generating Station.

Biocides will also be injected into cooling tower water to control algae growth. These chemicals also will be a constituent of the drift and will

'O be deposited in an area around the towers.

Drift depositions from these towers may result in changes of chemical constituents within the vegetation. For example, deposition of jO some salts on vegetation may result in their absorption and a reduction of root absorption of other essential nutrients. This could result in

O

v, 140 less vigorous plants. Heavy metals may also increase in vegetation as a result of drift deposition. These heavy metals may then be passed on to e' consumer animals in the area.

Little research work has been conducted to evaluate cooling tower drift effects on vegetation. It was, therefore, considered desirable to have g an inventory of the ecophysiology of the vegetation which might be affected by water vapor and salt deposition as a result of cooling tower opera tions . Since all animal life is dependent either directly or g indirectly upon vegetation as a source of food, decreased productivity or palatability of vegetation may be detrimental to animal populations. In addition, operation of the cooling towers may result in increased humidi- g ties and temperature changes in the immediate surrounding environment.

Since the St. Vrain Nuclear Generating Station is in the Denver Air Pollution Corridor, increased humidity could interact with vegetation, ,

resulting in increased leaf injury caused by the air pollutants. Numerous studies have indicated that a significantly-detrimental interaction exists between air pollutants and humidity which can cause severe damage to ,

photosynthetically-active tissues.

OBJECTIVES e

The objectives of this study were:

1. To determine leaf injury by pollutants, disease, and insects for certain species surrounding the Generating Station.

9

2. To determine concentrations of important elements in foliage of several species as related to distance and direction from the Generating Station.

O O

O 141 LEAF INJURY Leaves of cheatgrass (Bromus tectorum), kochia (Kochia scoparia),

and cottonwood (Populus sargentii) were collected from a maximum of 32 locations on four radii at distances of 1/8,1/4,1/2 and 1 mile from the Generating Station during rapid spring growth from 1972 through 1979 (Figure 1). Sampling of kochia and cottonwood at these same locations was again repeated when vegetation was mature in August. Fifty leaves were taken from each location at each sampling period. Estimates were

)

made of each leaf sampled for total leaf area, leaf area injured by chew-ing insects, and leaf area spotted caused by air pollutants, disease, nutrition, and sucking insects.

O A literature search indicated that pinto bean plants were sensitive to air pollutants. As pinto beans are an important crop produced in the area around the St. Vrain Nuclear Generating Station, they were utilized during 1973,1974,1976,1977,1978 and 1979 in a controlled experiment to determine effects of air pollution and drift at varying distances and directions from the cooling towers.

Pinto beans were planted in polyethylene-lined #10 cans in the greenhouse. All plants receivcd similar treatment in the greenhouse until mid July, when plants and containers were transported to the St. Vrain study site. Sixty-four containers with bean plants (four containers / location) were placed at two distances and eight directions from the cooling towers. Distances from the towers were 50 feet and 3 1/4 mile. The bean plants all received similar amounts of supplemental fertilizer, insecticide, and water. They were allowed to grow for approximately six weeks during each year at the study area. At that time, leaves from each plant in each container were sampled to detennine q

142 O

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Figure 1. St. Vrain study area showing locations of collection sites. el

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9 143 leaf injury. Ten to 20 leaves from each location were collected each g year. However, because of large numbers of grasshoppers feeding on the plants in 1979, only enough samples remained for chemical analyses.

Wet bulb and dry bulb temperatures at each location for pinto beans were measured in 1976,1977,1978, and 1979, each time bean plants were watered. Data were collected using a portable psychrometer. Utilizing these data, relative humidity and dew point temperature were calculated s to aid in determining the sphere of influence around the cooling towers.

Cultural practices such as crop rotation, fertilization, irrigation, and use of insecticides that could influence leaf injury and chemical constituents of vegetation were beyond the control of the investigator.

Therefore, quantitative data for agronomic species grown in the study area were not taken. The three naturally-occurring species utilized in this study were select (d because of their wide distribution and abundance on the site. In addition, other studies have indicated that Bromus tectorum and Phaseolus vulgaris are sensitive to air pollutants.

ELEMENTAL CONCENTRATIONS IN FOLIAGE Chemical analyses were conducted on foliage samples of kochia and cottonwood collected at maturity from each of the permanent sampling locations shown in Figure 1. Aboveground biomass samples of pinto bean plants in the controlled experiment were collected after six weeks of growth. All samples were dried at 60 C, ground to pass through a 40-mesh screen, and stored in glass jars. Chemical analyses indicated concen-trations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca),

magnesium (Mg), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), sulfate (SO4

-S), mercury (Hg), lead (Pb), cadmium (Cd) and boron (B) in plant

144 O tissue. These analyses indicated whether concentrations of various nutritive and toxic elements were influenced by either distance or 8 direction from the Generating Station through the years of the study.

However, not all chemical determinations were conducted for each species during each year. A brief description of the analytical techniques #

utilized by personnel of the Front Range Laboratory in Fort Collins, Colorado, in analyzing these samples is given in Table 1.

4 DATA ANALYSIS Data on leaf injury and chemical constituents of vegetation prior to electric power generation (1972-1976) were compared with data collected 9 during the station start-up phase (1977-1979). Analysis of variance was utilized to detemine if statistically significant differences for any chemical constituent of vegetation or leaf injury occurred as related to 9 year, distance, or direction from the Station. When significant (p < 0.05) conservative F values were found, Tukey's test was utilized to separate significant (p < 0.05) mean differences. 3 RESULTS AND DISCUSSION Blowers on the cooling towers were usually not in operation and water g was only being circulated through the towers during 1973 through 1977.

However, the blowers generally were in continucus operation in 1978 and 1979. Ambient environmental conditions (relative humidity and temperature) ,

surrounding the cooling towers were found to not vary significantly (p 0.05) during the study in 1976 and 1977. In 1979, wet bulb and dry bulb temperature was found to increase significantly (p 0.05) with ,

distance from the towers, whereas dew point temperature decreased O~

O-145 Table 1. Procedures anc equipment utilized oy the Front Range Lao Inc. In analyzing plant samples.

O Procedure Irstrumentation References Param.eter Calcium Nitric-Perchloric Acid Perkin-Elmer 5000 Coloraco State University soil (Ca) Digestion, Atomic A.A. Spectropnotometer Testing Lao, Plant Analysis Absorption (A.A.) Procedure August,1971; Quantification Pertin-Elmer A.A. Metnoos Manal, 1979.

O Magnesium Nitric-Percnloric Acid Perkin-Elmer 5000 ;oloraco State university soil (Mg) Digestion, Atomic A.A. Spectropnotemeter Testing '.ac, Plant Analysis Absc *ption (A.A.) Procedure, August.1971; Quanti fica tion Perkin-Elmer A. A. Metncds Manual, 1979.

Potassium Nitric-Perchloric Acid Perkin-Elmer 5000 colorado State University Soil 9 (K) Digestion Atomic A. A. Spectrognotcmeter Testing Lao, Plant Analysis Absorption (4.A.) Procedure August, 1971; Quantification Perkin-Elmer A.A. Metnces Manual, 1979.

Zinc Nitric-Perchloric Acid Perkin-Elmer 5000 Coloraco State University Soil (Zn) Digestion Atomic A.A. Spectropnotometer Testing Lao, Plant Analysis Absorption (A.A.) Procecure August, 1971; g Quantification Perkin-Elmer A.A. Metnods Manual, 1979.

Iron Nitric-Perchloric Acid Perkin-Elmer 5000 colorsoo State University soil (Fe) Digestion, Atomic A.A. Spectrocnotometer Testing Lao, Plant Analysis Absorption (A.A.) Procedure August,1971; Quantification Perkin-Elmer A.A. Metnods Manual, 1979.

Copper Nitric-Perchloric Acid Perkin-Elmer 5000 Colorado State University soil (Cu) Digestion, Atomic A.A. Spectropnotometer Testing Lac, Plant Analysis Absorption (A.A.) Procecure August, 1971; Quantification Perkin-Elmer A.A. Metnods Manual, 1979.

Manganese Nitric-Perchloric Acic Perkin-Elmer 5000 coloraco 3 tate university Soil (Mn) Digestion, Atomic A.A. Spectroonotometer Testing Lab, Plant Analysis O Abscrption (A.A.) Procedure, August,1971; Quantification Pertin-Elmer A.A. Methods Manual, 1979.

Land Nitric-Perenloric Acid Pertin-Elmar 5000 Colorado State University Soil (Pb) Digestion, Atomic A.A. Scectropnotomet. Testing Lab, Plant Analysis Absorption (A. A.) Procedure, August, 1971; Quantification Perkin-Elmer A.A. Methocs

' Manual, 1979.

Cacmium Nitric-PercM oric Acid Pertin-Elmar 5000 Colorado State University soil (Cd) 3tgestion Atomic A.A. Spectropnotometer Testing Lac, Plant Analysis Absorption ( A. A. ) Procecure. August, 1971; Quantification Penin-Elmer A.A. Metnocs Ma nual , 197 9.

!'ercury Aqua-Recia Digestion, Jarrell-Ash 310 Colorsoo State 'Jniversity Soil (Hg) Atomic Absorption A.A. Soectrophotometer Testing Lao, Plant Analysis (Cold Vapor Metrod) Procecure August, 1971; Jarrell Asn Metnces Manual, 1971 (Fisner Scientific Co.)

a cron ;ry Asning, Curcumin Coleman Linear Coloraco State ;niversity toil (3) Colorimetric Soectroonotometer Tasting .ao, Plant Analysis

)

Ceter91 nation Procecure August, 1971.

Sulfate Jilute .1C1 Extraction. Coleman L*nese Colo-aco Stata University Soi! l (50,-5)

Turoidimetric Soectroonotomete r Testing Lao, Plant Analjs s l Oeter :ina cion Peccecure August, 1971. 1 l

1 1

O' 146 i

Table 1.--Centinued Para..eter Procedure Ins trumeinta tion References Phospnorus Vanadomolybdognosphoric Coleman Linear Colorado State University soil (P) Yellow HNO3 Method Scectropnotometer Testing Lac, Plant Analysis Procedure August 1971.

Nitrogen Micro-Celdani Sa rgent-aelsh A.S.A.,.N nogr. No. 3.

(N) Recording Titrator p. 1196, 1965.

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147 significantly with distance (Table 2). Relative humidity was slightly greater'and dew point temperatures were slightly lower near the towers as 3

compared with data collected at 1/4-mile distance in 1976, 1978, and 1979, whereas the reverse was true in 1977. It therefore appears that the g major sphere of influence around the cooling towers is within 1/4-mile distance of the towers.

Water samples were taken in 1979 from the cooling towers to compare with makeup water from the St. Vrain and South Platte Rivers, and irriga-3 tion water in Goosequill Ditch where blowdown water is received. The four locations were sampled once in both July and August. These samples were analyzed for total phosphorus (P), magnesium (Mg), sulfates (504 -S) j and electrical conductivity (EC) by the Front Range Lab., Inc. Al though sample size was small, these data indicated that total phosphorus, sulfate, and e: ._t conductivity (i.e., salts) were at least twice as high in cooling tower water as in makeup water or diluted blowdown water (Table 3). We might therefore expect drift from the cooling towers to have a nigher concentration in several elements and salts. This drift would be O

deposited on vegetation, other objects, and on soil in an area surround-ing the towers. Drift at any one time would, however, be highly dependent upon prevailing weather at the time.

u LEAF INJURY CAUSED BY POLLUTANTS, DISEASE AND INSECTS Natural Veaetation O

Statistical analyses of all leaf data for each year of the study have been completed. As expected, highly significant (p<0.01) differences existed for most leaf measurements among the eight years of data collec-O tion even when a conservative F-test was utilized. This indicates the i

Q

148 Table 2. Average environmental conditions du;ing a six-week period in 1979 at varying distances and directions from the cooling towers of the fiuclear Generating Station. ,

Ambient Environment Distance Direction Wet Bulb Dry Bulb Relative Dew Point Cooli,9 Cooling Temp Humidity Temp Tgmp Towers Towers

( F) ( F) (5) ( F; e I

50 feet 67b 83b 47a 59b 1/4 mile 69a 87a 45a 61a

^

9 l 45a 60a N 67a 85a NE 67a 84a 46a 59a E 68a 85a 46a 60a SE 68a 86a 45a 60a S 67a 86a 44a 59a SW 69a 85a 48a 61a 9

W 68a 86a 46a 60a NW 68a 86a 45a 60a I Numbers in a column followed by similar htters are not signifi- 9 cantly different at the 0.05 level of probability.

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j 149 Table 3. Chemical concentrations in water samples taken from four locations near the Nuclear Generating Station in July and j ,- August, 1979.

Location Month Total P Mg SO4-S EC (mg/1) (mg/1) (mg/l) (mhos/cm) j St. Vrain River 1.2 68 51 3 1421 South Platte River 1.4 18 304 1137 Blowdown ditch 1.4 22 436 1452 Cooling towers I 2.8 52 1296 3789 July 1.7 40 850 1950 August 1.7 40 425 O

I The Fort St. Vrain cooling towers are designed to operate so as to utilize water 3 to 5 times to conserve water. This will, therefore, concentrate chemicals within the cooling tower water.

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150 L high degree of jearly variation that influences leaf growth and injury.

Distance and direction from the Generating Station were usually not ,

significant (p>0.05) variables in affecting leaf injury, either before or after the Station began to generate electrical power in December 1976.

In general, leaf area of cottonwood increased from May or June ,

through August. Kochia, however, had smaller leaf area per leaf in August than in May. No significant trend in leaf area per leaf for cheatgrass or cottonwood was found as related to distance from the station. In some years, leaves were larger near the Generating Station, whereas in other years they were larger at the 1/2- and 1-mile distance from the station. Leaves of kochia tended to be somewhat larger during O

the eight years of sampling at the 1/2- and 1-mile distance from the Generating Station.

Cheatgrass leaves were larger in a south through a northeasterly 9

direction from the Generating Station. Leaves of both kochia and cotton-wood were often larger in a southeasterly direction. This may be related to intensive farming and irrigation practices occurring southeast of the O

Generating Station during the years of the study.

The percentage of leaf area removed by chewing insects increased for both kochia and cottenwood between rapid growth and maturity during O

six of the eight years of study. This was very evident during 1979 when large populations of grasshoppers fed on kochia. Cheatgrass leaf area removed by insects was about the same near the Generating Station as at 9

greater distances. In contrast, chewing insects usually removed more leaf area of kochia at the 1/8- to 1/2-mile distance from the Power Station. Leaf area missing for cottonwood as related to distance from the Generating Station showed no trend. Removal of cheatgrass leaf area O

1. 151 by insects was greater in a south and southwesterly direction from the Generating Station in five of eight years of sampling. No consistent directional trend in leaf area removal among the years was found for kochia or cottonwood. Therefore, there was no consistent distance or directional influence from the Generating Station affecting insect leaf removal among the three species.

Brown tip leaf area and leaf sootting for kochia was greater by an order of magnitude in 1978 and 1979 than in previous years. This O

resultea primarily from storage problems in 1978 and insect feeding activity in 1979. Brown leaf tips of kochia were also often greater in a south through west direction. This same trend was also noted for cotton-O wood. This trend might be related to less intensive agricultural activity in a southwesterly direction from the station.

Leaf spotting may be the better indicator of leaf injury caused by D

pollutants or cooling tower drift. A significant (p<0.05) effect as related to distance from the Generating Station was detected for leaf spotting of cheatgrass and kochia. No significant differences for leaf spotting of cottonwood were found as relatet to distance from the station.

Although there was a difference in leaf spotting of cheatgrass as related to distance, no consistent trend in the data were apparent. Leaf spot-ting was sometimes greatest at further distances from the station for the June collection of kochia, but spotting was greatest at 1/8 to 1/2 mile by the time of the August sampling period.

Leaf spotting of cheatgrass and kochia was not related to direction from the Generating Station. However, leaf spotting for cottonwood was related to direction from the station and was usually more pronounced in a north through east direction from the station. ibis would be downwind sJ

152 1 from the station as the prevailing wind during the growing season is from the southwest.

O Data for various leaf characteristics were compared utilizing a conservative F-test for two time periods: before (1972-1976) the station generated electrical power and after (1977-1979) startup of limited power generation. Leaf area of cheatgrass was similar for the two time periods; whereas, leaf area of kochia declined and that of cottonwood increased significantly after the station began operation (Table 4). A greater percentage of leaf area was removed by insects using kochia after the 8 station began operation, and the opposite trend was evident for cotton-wood. Leaf spotting and brown tips were both greater for cottonwood before the station began power generation. However, percentage spotted

• leaf area for both cheatgrass and kochia were greatest after the station began operation (Table 4). These data clearly illustrate the varied species responses that were obtained in this study. No apparent trend #

was evident among species, and it appears that the differences resulted primarily from causes other than operation of the Nuclear Generating Station. 9 It appears that leaf injury of the three naturally occurring species during the past eight years has been happening somewhat at random about the Generating Station. Intennittent and limited Generating Station 8 operations varying from shutdown up to a maximum of 70% have not as yet resulted in the type of data that would be suitable for response analysis in determining leaf injury. Microclimatic differences, site characteris- 9 tics, and agricultural activity appe&c to be the major factors causing any significant distance, directional, and yearly effect observed to date for leaf injury. 4 1

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153 Table 4. Average leaf characteristics for three naturally occurring species collected at maturity near the Nuclear Generating

1. Station before (1972-1976) and after (1977-1979) beginning of operation of the station.

Before/After Leaf Area (mm)  % Missing  % Spotted  % Brown Tip G Bromus tectorum Before 109a l 0.8a 5.0b 14.8a After lila 1.4a 15.2a 20.2a G Kochia scoparia Before ll5a l 0.9b 3.3b 1.9a After 70b 6.0a 7.8a 2.5a e Populus sargenti l 1.4a 3.9a 0.2a Before 2837b After 5555a 0.3b 1.6b 0.lb I

g Means for a species in the same column followed by a similar letter are not significantly different at the 0.05 level of probability.

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Pinto Bean Experiment Analysis of data for various leaf characteristics of pinto beans in g the controlled experiment indicated that neither distance nor direction from the cooling towers significantly (p<0.05) affected most leaf characteristics, except for leaf area. Leaf area of individual leaves g were smaller (360 mm) near (50 feet) the cooling towers as compared with leaves that had grown at 1/4-mile distant (460 m) from t.he towers. As expected, significant differences among years for several leaf charac- g teristics of pinto bean pl6nts were probably caused by differences in growing conditions, insect activity, and status of tower operation during the five years of study (Table 5). g ELEMENTAL CONCENTRATIONS IN VEGETATION Kochia scoparia Analyses of data for elemental concentrations in foliage samples of kochia collected each August during six years indicated that nitrogen (N), sulfate (SO4-S), mercury (Hg), lead (Pb), and boron (B) all varied ,

significantly (p<0.05) through time (Table 6). However, only sulfate varied significantly with distance from the station when a conservative F test was used in analyzing these data. Sulfate was often more concen-9 trated in kochia foliage at a one mile distance than closer to the station. No other chemical constituent varied significantly with either distance or direction from the Generating Station. Sulfate concentrations O

increased in foliage through time resulting in a greater concentration in foliage after the Generating Station began operation (Table 6). Somewhat of a reversal of this trend was noted for nitrogen and mercury as higher o;

concentrations were recorded before the station began operation.

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.D . 155 Table 5. Average leaf characteristics for pinto bean plants (Phaseolus vulgarj_s) s collected at maturity at varyin9 distances from the 1 r: Nuclear Generatin9 Station for 1973 through 1978.  !

O Distance Year 50 feet 1/4 mile Q 2 Leaf area (nin )

1973 775b] 1129a

! 1974 921a 1086a 1976 253d 403bc j 1977 478c 460b 1978 205d 320c l

l Leaf area missing (%) j l 1973 0.79a 4.31a D 1974 0.27a 0.78a 1976 0.74a 0.49a 1977 0.59a 0.15a 1978 0.81a 1.33a

'O Leaf area spotted (%)

1973 6,74a) 3.92a 1974 1.32b 1.25a 9 1976 2.39b 3.04a 1977 3.73b 3.34a 1978 1.45b 1.61a V Brown tip leaf area (%)

1973 I 1.88a 1.77a 1974 0.74a 1.05a 1976 1.16a 1.07a 1977 1.24a 0.91a O 1978 1.64a 0.79a I

Numbers in a column followed by similar letters are not signifi-cantly different at the 0.05 level of probability.

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C; 156 Table 6. Averagc concentration of various elements in foliage tissue of kochia Mochia secoaria) during six years and as related to before (1973-1976) land after (1977-1979) beginning of operation ,

of the Nuclear Generating Station.

Year or N SO4 -S Hg Pb Cd B

" (ug/9)

E*$#

S at (%) (%) (99/9) (99/9) (99/9)

S 1973 --- ---

0.23a 1.42b 0.38a 74.lbc 2

1975 2.81c 0.40c 0.14b 0.70bc 0.31a 51.6d 1976 4.29a 0.37c 0.12bc 0.23c 0.29a 92.5ab ,

1977 3.62b 0.47bc 0.09bcd 0.12c 0.25a 102.2a 1978 2.72c 0.53b 0.12bc 0.82bc 0.62a 69.2cd 1979 1.26d 0.97a 0.05d 3.04a 0.51a 63.6cd ,

Before 2

(1973-1976) 3.56a 0.38b 0.16a 0.89a 0.32a 73.0a After (1977-1979) 2.58b 0.64a 0.09b 1.26a 0.46a 78.9a #

I Data were not collected in 1974 because an insufficient amount of leaf material remained for analysis, 2 O Numbers in a column followed by a similar letter are not signifi-cantly different at the 0.05 level of probability.

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157 Populus sargentii

• Elemental concentrations in foliage samples of cottonwood collected each August for 1974 through 1979 are shown in Table 7. Nitrogen (N),

phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe)

' and copper (Cu) all exhibited varying concentrations through the six years. Nitrogen, potassium, and baron were all higher in foliage before (1974-1976) the station began operation, whereas phosphorus, iron, and 3 sulfate were more concentrated in samples after (1977-1979) the Generating Station began operating. Potassium and calcium were usually more con-centrated in cottonwood foliage near (1/8-1/4 mile) the station, but J magnesium, zinc, manganese (Mn), and boron were usually higher in foliage at a distance of one mile from the station. It then appears that station operation to date has had little direct effect on elemental concentrations

) as related to distance from the station.

Significant directional effects were detected for concentrations of nitro' gen, magnesium and zinc. Nitrogen was usually higher in a northeast

'e through southeast direction from the station. Magnesium was more concen-trated in cottonwood located southwest through northwest of the Generating Station. Zinc concentrations in foliage were consistently lowest in a j northerly direction from the station. It therefore appears that the limited station operation to date has not affected directional distribution of elements in cottonwood foliage, as prevailing winds are usually southerly 3 or westerly during the growing season.

Phaseolus vulgaris 77 More elements were different in concentrations among the six years of study for pinto bean plants in the controlled evperiment than for h-

Table 7. Average concentrations of various elements in foliage tissue of cottonwood (Populus sargentii) over a six year time period and as related to before (1974-1976) and after (1977-1979) beginning of limited operation of the Nuclear Generating Station.

Year or ti P K Ca Mg Zn Fe Mn Cu SO4 -S B Status I) II) () I) () ("9/9} I"9I9} ("9 9 "9 9 (%) "9 9 1974 2.39a l 0.07d 1.41b 2.51a 0.53ab 109.4a 81.8b 41.2a 7.4b 0.46a 113.Sa 1975 2.15ab 0.25bc 1.26bc 1.57b 0.33c 83.9a 82.2b 49.la 10.7b 0.49a ll7.8a 1976 2.37a 0.32b 1.85a 1.64b 0.36c 75.4a 93.7b 41.4a 10.4b 0.51a 104.la 1977 1.88bc 0.51a 1.43b 1.77b 0.48abc 86.7a 68.3b 32.Sa 5.9b 0.70a 94.6a 1978 1.85c 0.18c 0.98c 2.41a 0.57a 102.5a 85.8b 44.0a 7.7b 0.78a 105.5a 1979 0.80d 0.17c 1.24bc 1.45b 0.39bc 81.4a ll 39.4a 37.9a 19. 3a 0.83a 74.6a 8efore (1974-1976) 2.31a l 0.21b 1.50a 1.92a 0.41a 89.9a 85.8b 40.9a 9.5a 0.49b 111.8a After (1977-1979) 1.56b 0.29a 1.22b 1.89a 0.48a 90.3a 417.8a 38.2a 10.8a 0.77a 91.9b INumbers in a column followed by a similar letter are not significantly different at the 0.05 level of probability.

O # $ 9 9 9 9 9 8 $ $

l 159 either kochia or cottonwood. Nitrogen, phosphorus, potassit.m. calcium, magnesium, zinc, iron, manganese, copper, sulfate, mercury, lead, and cadmium (Cd) all varied significantly through time (Table 8). In fact, the only element that did not show any significant concentration changes during the study period was boron,as boron concentrations were highly variable.

The only obvious trend in these data was the increase in sulfate concen-

~

trations from 1974 through 1979. Sulfates increased from 0.20 pg/g to 4.37 ug/g during this five year period. This same significant trend was also observed in the naturally occurring kochia and cottonwood species (Tables 6.and 7). This significant increase in sulfate concentrations in all species may be related to increasing sulfur dioxide air pollution in O

the Denver metropolitan area which is likely affecting vegetation near the Nuclear Generatina Station.

Phosphorus, calcium, zinc, iron, and sulfate were all more O

concentrated in aboveground biomass of pinto bean plants after (1976-1979) the Generatino Station began operation than before (1973-1976)

(Table 8). Nitrogen and potassium concentrations in biomass were, however, higher before the station began operating. Various salts in the drift from the cooling towers were probably at least partially respon-sible for the increased concentrations of the five constituents. A pre-q liminary study indicated that cooling tower water was at least twice as high in phosphorus, sulfate, and electrical conductivity as was the makeup water from the St. Vrain and South Platte Rivers (Table 2). Less nitrogen ani potassium in the plants may either be a dilution effect or may be relate 1 to smaller leaf size of plants grown near the cooling towers.

3 D

Table 8. Average concentrations of various elunents in aboveground biomass of pinto bean plants (Phaseolus vulgaris) during six years and as related to before (1973-1976) and after (1977-1979) beginning of operation of the ftuclear Generating Station.

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

ear or Zn fe Ho Cu 50 -S lig Pb Cd 8 il P K Ca KJ

""$ta t(("

(%) (%) (%) (%) (%) ("9/9) (99/9) (99/9) (99/9) () (99/9) (u9/9)("9/9I(99/9)

I 30ld 52.0cd 10.2c 0.25a 1.4b 0.Sc 59.0a 1973 2.96b 0.40b 2.75b 1.49d 0.56b 55.3b ---

1974 3.08b 0.38b 2.39b 3.26b 0.65b 38.0c 410d 37.5d 8.4c 0.20c 0.09c 1.4b 0.7b 60.9a 1976 4.26a 0.36bc 3.61a 2.04cd 0.39c 49.7b 968b 75.3b 15.2n 0.50c 0.10bc 1. l b 0.2d 76.4a 197/ 2.94b 0.78a 2.52b 1.60d 0.39c 58.2b 317d 35.3d 8.lc 0.58c 0.llbc 0.3b 0.2d 15.0a 1978 3.06b 0.30c 2.34d 4.18a 0.88a 120.2a 589c 65.0bc 10.6c 1.59b 0.10bc 1. l b 0.7b 65.2a b 1979 1.30c 0.34bc 1.50c 2.56c 0.57b 122.4a 3004a 146.0a 3fi.4a 4.37a 0.21ab 12.Sa 1.3a 152.Sa 6efore I (1973-1976) 3.38a 0.38b 2.94a 2.02b 0.53a 50.0b 525b 56.0a ll.3a 0. 3'ib 0.17a 1.29a 0.4a 64.6a After (1977-1979) 2.58b 0.53a 2.22b 2.61a 0.58a 92.5a 1051a 71.2a 16.2a 1.80a 0.13a 3.48a 0.6a 63.Sa I tlumbers in a column followed by a similar letter are not significantly different at the 0.05 level of probability.

3 161 There was a weak trend in these data which indicated that g concentrations of nitrogen, magnesium, iron, manganese, copper, and sulfate were greater in pinto bean plants grown near the cooling towers (50 f t) as compared with plants grown at 1/4 mile distance from the g towers. This was expected as drift deposition at 50 feet from the towers was heavy at times. The amount of drift deposition had certainly declined by 1/4-mile away from the towers.

9

SUMMARY

AND CONCLUSIONS In general, leaf area injured decreased with time during the growing seasons during most of the years of study. This was anticipated g

as leaves are more susceptible to injury while they are growing and

! before they reach maturity. Some leaf injury measurements for the three

, naturally occurring species showed significant differences for distance v

from the St. Vrain Nuclear Generating Station. But, it appeared that leaf injury was not related to direction from the Generating Station.

Therefore, it appears that most variations in leaf injury were caused by O

microclimate, site, insects, and species differences and were little influ-i- enced by the intennittent, limited operations of the Generating Station to date.

Leaf area of pinto beans in a controlled experiment were often U

smaller when grown near (50 feet) the cooling towers. However, increased leaf spotting near the towers was observed only in one of the five years of study. Cooling tower blowers were usually not in operation during Q,

earlier years and humidity near the towers was only slightly greater during 1978 and 1979 than at the 1/4-mile distance from the towers.

These relationships might become more pronounced when the Generating O

Station reaches full power operation. The Nuclear Generating Station has O

162 (

had only intermittent, irregular, and limited operation to date (1977--

177 days, 1978--201 days, and 1979--77 days). g Elemental concentrations in foliage samples of kochia and cottonwood were little influenced by distance or d'rection from the St. Vrain Nuclear Generating Station. Although significantly higher con- g centrations of some elemen'.s were found in foliage from some local sites, there was no consistent trend in these data among the elements and sites or as related to prevailing winds during the growing season. The most ,

obvious trend in these data is the significant increase of sulfate in foliage of both species during the past few years. Sulfate concentra-tions have nearly doubled during the past six years. This is probably , ,

indicative of increased levels of air pollution in the Denver Air Pollu-tion Corridor. Sulfate levels in vegetation may prove to be a good integrated index for monitoring ambient levels of air pollution.

Five chemical constituents (phosphorus, calcium, zinc, iron, and sulfate) in pinto bean plants from the controlled experiment increasej in concentration after startup of the Generatino Station. Since water O

samples from the cooling towers had levels of phosphorus, sulfate, and salts that were at least twice as high as makeup water from the two rivers, it is probable that drift deposition on foliage was at least O

partially responsible for this increase. Heavy metal concentrations in pinto bean plants of mercury (Hg), lead (Pb) and cadmium (Cd) were not different before norafter station startup. However, a significant 9

increase in all three of these heavy metals was detected in 1979. A larger difference in temperature and humidity also was detected around the cooling towers in 1979.

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MAMMALS, AMPHIBIANS AND REPTILES O

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by Bruce A. Wunder O

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164 INTRODUCTION O

My participation in and initiation of the Mammal, Amphibian and Reptile portion of the Fort St. Vrain Biological Inventory and Monitoring Program began in Spring 1972 to determine the effects of the Nuclear g Generating Station operations on these vertebrates. At that t'ne (March 1972) it was expected that the Station would be in full operation by Fall 1972 and that monitoring might extend for one year beyond. g The goal was to determine which species were present on the Station property and where they were found, as the species lists given in the initial impact statement were obviously based on outdated species dis- ,

tribution maps and little or no on-site evaluation. One month was spent trapping and observing in the various habitat types, reading reports on how the Station was to function, hypothesizing how the Generating Station ,

might affect the environment and hence the animals. We decided to assay species presence for large mamals, reptiles, and breeding amphibians and to concentrate numerical population analyses on small mammals. Large O

mamal densities on and use of the Station property and surrounding areas seemed low enough that for a 1 to lh year study, species presence seemed sufficient. Furthemore. :;ince large mammals are so mobile and range over G

large areas, it would bs difficult to confine influence on their numbers just to factors on the Public Service Company (PSC) property. Given the apparent densities of reptiles and amphibians, we settled on as saying 9

species presence.

Short of a major radioactivity or reactor mishap, it appea*ed that the major aspects of the Station operation which might affect sertebrate O

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populations were those associated with cooling-tower water. Water is

• evaporated taking with it salts and other materials which may be subse-quently deposited on neighboring vegetation and then be consumed by foraging mammals. Additionally, heavy metals and sub-biocides could

• leach into soils along the irrigation ditches and in Goosequill Pond, subsequently to be concentrated in plants eaten by animals or taken up by arrhibians in the water. Consequently, amphibians breeding in Goose-8 quill Pond and along the ditches were assayed. For these reasons and because small mamals and amphibians provide a food base for mammalian and avian predators in the areas, we also studied heavy metal concentra-

1. tions in the two groups to provide baseline comparison with similar data obtained during operation of the Nuclear Generating Station.

METHODS j

Items Sampled The goals of this section of the monitoring project were as follows:

a 1. Monitor species presence or absence of large mamals, reptiles and amphibians, particularly breeding populations.

2. Monitor population numbers and trends in small mammals. The

reasons for emphasizing small mammal populations were as follows

a. There are good data validating population sampling 1, techniques.

b. The animals forage on plants and their seeds, which may be affected by " drift" and/or " blowdown" water from the Generating Station.

1

166 L

c. The animals do not move great distances and thus changes in population densities should be due to factors in the 9 immediate environment.

3. Detemine concentrations of copper, zinc, and lead in various tissues of prairie voles (Microtus ochrogaster) and Woodhouse's 9 toads (Bufo woodhousei). These three heavy metals were reported in the water to be used for cooling and hence could potentially be concentrated during Station operation. All are toxic in e high cotcentration to vertebrates. Prairie voles were common in dense vegetation along the irrigation ditches and fed on that vegetation. Woodnouse's toads were connon breeders in 3 most of the water areas.

The detailed methods of detemining species presence and small mammal population parameters have been presented in progress reports on the Fort e St. Vrain Nuclear Generating Station (December 1973 and June 1974). Like-wise, details of sample preparation and heavy metal analysis (performed by the Colorado State University Analytical Chemistry Lao) were given in the g December 1974 Fort St. Vrain Progre;s Report.

The present techniques for small mammal population analysis have remained the same since 1972. ,

Sampling Periods One or two trips per month were made to the PSC property to assay species presence. And, three times per year, five-day sampling O periods for small mammal densities were undertaken: (1) late May-early June (late Spring) to determine numbers following Spring breeding; (2)

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167 early September (early Fall) to assay population levels following sumer breeding; and (3) late November (late Fall) to determine population numbers entering the winter.

Sampling Site placement Sampling sites were located as indicated in Figure 1. These locations were chosen compromising two factors: equidistant points and compass directions from the Nuclear Generating Station. However, the symetric selection was influenced by the need for large blocks of similar vegetation l for trapping that would not be affected by day-to-day fanning activity.

l In addition, because of some species specificities, as many vegetation types as possible were trapped. Where there were large enough areas of homogeneous vegetation,10 X 10 station trapping grids were established.

Where areas were not adequate, then North American Census of Small Mamal Lines were established as indicated in the December 1973 Progress Report.

CHANGES IN MONITORING PROCEDURE During the course of the study, three major changes in monitoring procedure occurred:

1. Elimination of two sampling sites--Following the Sumer of

)

1973, Grid 2 and North American Census Lir.e 6 (Fig.1) were abandoned as sampling sites. The Spring of 1973 was wet with I

considerable flooding and these two sites (in the South Platte k River floodplain) were completely under water during the June sampling period and had large areas of surface ponds into Sumer and Fall.

168 O

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FIGURE LEGEND 9

Transect 1 - Cropland - pasture

2. Vegetation along irrigation diten 3 - River bottom

4. Vegetation along irrigatien ditch 5 - River bottom 6 - River bottom 7 Vegetation near farm pond 8 - Cropland pasture g Grid 1 Cropland (Old fleid) 2 River bottom 3 - Pasture E GRID O NACSM S Figure 1. Fort St. Vrain Nuclear Generating Station study area--

pennanent trapping areas and habitat descriptions. g l

9

m-l

) 169 l

2. Elimination of March (early Spring) Sampling Period--We had

) initially planned four trapping periods each year with one scheduled for early Spring to assay population levels following the winter and before Spring breeding. These were scheduled

) for early March. However, in March 1973 weather was so incle-ment that many animals died in the live traps during sampling.

Because many deaths at this time would affect the Spring D breeding populations adversely, the sampling period was dropped.

3. Hedvy Metal Analysis--Following our conclusion that concentra-tion of materials in " blowdown" water may be amplified and e increased in concentration in small mannals and amphibians and have adverse environmental effects, we proposed to monitor levels of copper, zinc, and lead in these animals. These g studies were initiated in 1974 and ended in 1977; however, we were able to analyze animals collected and frozen from 1972-1976. Monitoring ceased in 1977 primarily for financial reasons but also because good baseline data were available for 3

comparisons, RESULTS AND DISCUSSION O

Mammals: Species Presence Table 1 lists the manmals which we have confimed to be utilizing g

L the Nuclear Generating Station environs from 1972-1979. All of these species were still detemined to be present on the PSC property during 1979 except those species listed in Table 2. For reasons discussed in g the December 1979 Progress Report, most of those species may still be found on the property with the exception of the thirteen-lined ground D

[ v 1 170 -

Table 1. Mamals present in the vicinity of the Fort St. Vrain Nuclear Generating Station.

O Comon Name Scientific Name Presencel Abundance 2

1. Shrew sore sp. 1. C R

2. White-tailed jackrabbit Icas counsendii 2. V P ,

3. Black-tailed jackrabbit Lepus eatifornicus 3. V P

4. Cottontail rabbit sylvilagus sp. 4. V A-P

5. Thirteen-lined ground spemophilus 5. C P squirrel tridecemlineatus

6. Spotted ground squirrel spemophilus spilocoma 6. C P

7. Rock squirrel spemophilus variegatus 7. V R g

8. Black-tailed prairie dog cynomys tudovicianus 8. V A(locally)

9. Fox squirrel sciurus niger 9. V A

10. Beaver castor c2nadensis 10. T P

11. Pocket gopher cecmys bursarius 11. C P(locally)

12. Harvest mouse Reichrodontomys sp. 12. C R

13. Deer mouse Peron~jecus maniculatus 13. C A e

14. Northern grasshopper anychcmse Zeucogaster 14. C R mouse

15. Prairie vole xierotus ochrogarter 15. C A-R

16. Meadow vole Microtus pennsylvanicus 16. C R

17. Muskrat endatra sibethicus 17. V-T P

18. House mouse Aus musculus 18. C- A-R g

19. Norway rat Rattus nor:egicus 19. C R

20. Meadow jumping mouse Zapus hudsonicus 20, C R

21. Coyote canis Ictrans 21. V-T R

22. Red fox vulpes vulpes 22. V R

23. Raccoon Procyon totor 23. T-S P

24. Long-tailed weasel Mustela frenata 24. V R e

25. Striped skunk Nephitis mephitis 25. T-0 P

26. Domestic cat Felis domesticu8 26. V P

27. Domestic dog canis familiaris 27. V-T P

28. Mule deer cdocotteus hemionus 28. T-S-D P

29. White-tailed deer odocoiIeus virginianus 29. V-T-S R-P

30. Badger Taxodea tarus 30. T-S P-R e I 2 C = Captured R = Rare D = Found Dead P = Present (moderately common)

S = Scat A = Abundant T = Track e V = Visual Observation 9

e

l 171 Table 2. Mammal species previously noted near the Fort St. Vrain Nuclear

,; Generating Station that were not censused in the first ten months of 1979.

~

Connon Name Scientific Name 3

1. Shrew Scre: sp.

2. Black-tailed Jackrabbit Lepus californicus

3. Thirteen-lined ground squirrel Spemophilus cridecemlinec us 4 Spotted ground squirrel Spemcphilus spiIcscmc

5. Rock squirrel Spermophiius ucriegc:us Cnuchemys ledcogcarer

^'

6. Northern grasshopper mouse

7. Noraay rat ?c::us norvegicus

8. tieadow jumping mouse 2cpus hudsonius

9. Long-tailed weasel haseIc frenc cE 3 E May have been present, as tracks were recorded, but species identification was not possible.

O O

O

,.) ..,

172 C squirrels and spotted ground squirrels. Both squirrels were common in the vicinity of Grid 3 and Transect 8 in the early years of the study S but have not been seen since 1976. The reason for the disappearance is not known. Since both are diurnally active and fairly conspicuous, I must assume that our not seeing them is justification to conclude they G are no longer present. Also, since no other species seem to be greatly affected and the prior relative numbers or presence-absence of these squirrels were greatly influenced by agricultural practices, I must e conclude that they have been driven out by changes in agricultural prac-tices and not by any direct function of the Nuclear Generating Station.

O Mammals: Populations Deer mice and house mice continue to be the most common small mammals on the PSC property. Their numbers have stabilized since late 1976 (Figure 2), thus these values provide a good baseline for future measurements.

One major population change since the initiation of the study was the reduction of the prairie vole numbers at the trapping sites. In the early years (1972-1974), prairie voles were always the second most numerous species; but following their almost virtual disappearance during late 1975 and again in 1977, they have been low in density. This species is O

known to show periodic population fluctuations and to need relatively moist habitat. Thus, it appears that the dry years on Grid 3 and the manipulation of Transect 7 (where many of these animals were caught) may have reduced numbers to levels from which the species has not been able 8 to recover. At present we have no reason to link this reduction to the intermittent and irregular operation of the Nuclear Generating Station.

O l

1. I

T g 173 O

4 -

t 280 - - -- - oeer Mice western Harvest Mice

- Prairie Votes

---

House Mice 3 240 -

a R E l'\

R 200 -

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1972 1974 , 1975 , 1976 , 1977 , 1978 , 1979 ,

3 C' YEAR D

Figure 2. Total number of small mammal individuals captured at the Fort St. Vrain Nuclear Generating Station: late Spring 1972 -

early Autumn 1979.

O

%)

174 C Table 3. Amphibians and reptiles present in the vicinity of the Fort St.

Vrain Nuclear Generating Station.

O Connon Name Scientific Name , Presence l 1 Spadefoot toad Scaphiopus bombifrons 1 V-C O

2. Great Plains toad Sufo cogna:as 2. C

3. Woodhouse's toad Sufo uoodhousei 3. C 4 Western chorus frog Pseudacris crisertat 4 C O

5. Bul1 frog Rana cceasbiana 5. C

6. Leopard frog Rana pipiens 6. V

7. Tiger salamander Ambystoma tigrinum 7. V O

8. Snapping turtle Chetydra serpentina 8. 0

9. Painted turtle Chrysemys picta 9. V-D

10. Spiny soft-shelled turtle n ionya spiniferus 10. V O

11. Racer Cotuber constrictor i1. V

12. Common garter snake Thamnophis sireclis 12. C

13. Plains garter snake Thc=nophis radi: 13. C O

14. Bull snake Pituophis meZawleucca 14. C

15. Western rattlesnake Crotalus viridis 15. V I O C = captured O = found dead S = scat T = track V = visual observation O'

O O

i' A

G 175 Amphibian and Reptile: Species Presence

• Table 3 lists the species of amphibians and reptiles that have been observed on the PSC property. Virtually all the amphibians and reptiles previously inventoried on the PSC property were inventoried during 1979.

8 The lesser earless lizard (Holbrookia maculata_), with only one previous sighting, and the western rattlesnake (Crotalus viridis), which probably still occur in low numbers, were the only reptiles not recorded. Spiny e soft-shelled (Trionyx spiniferus) and snapping turtles (Chelydra serpen-tine) were not seen but have never been abundant on the rivers since the floods of 1973. And the tiger salamander (Ambystoma tigrinum), not a recorded in 1979, has only been seen in the Nuclear Generating Station settling ponds which were not censused in 1979. Thus, it appears that Station operation has had no apparent effect on amphibian or reptilian a presence in the area.

Heavy Metal Analysis We were especially interested in answering two questions concerning U heavy metal concentrations in mamals on the PSC property: (1) are there differences in tissue concentration of specific metals for animals from different sites? and (2) are thye differences between years in these concentrations? To answer the first question we compared (using 2-tailed T-tests) levels of copper, zinc, and lead in liver and kidney of animals from Grid 3 and Transect 7. These sites were quite far apart and are 3 affected differently by water discharge patterns from the Nuclear Generating Station. No significant differences in any metal concentra-tions in either liver or kidney could be demonstrated (Tables 4 through 6).

3 Nr

176 O Table 4 Copper (Cu) concentrations in Microtus ochrogaster (pg/g).

9 Month Group N Tissue I S.D. Tissue I S.D. Tissue r S.D.

June All Sites 1972-74 11 Liver 16.5 3.6 Kidney 19.4 2.5 '0"9 - -

" Bones All Sites 1975 9 15.7 1.9 "

16.3 1.9 0.2 0.1 Grid 03 1972-74 5 14.4 2.1 "

19.0 2.9 " - -

O Grid 03 1975 2 17.5 3.5 "

17.5 0.7 "

0.2 0.1 Tran 07 1972-74 5 17.0 3.5 16.7 2.4 - -

Tran 07 1975 4 15.8 1.3 16.2 1.3 0.2 0.1 Sept. All Sites 1972-74 6 Liver 17.3 3.4 Kidney 17.3 1.9 '0"9 - -

All Sites 1975 7 16.1 2.2 "

16.3 1.1 8 ges 0.3 0.4 9 Grid 03 1972-74 3 16.7 3.1 "

16.7 2.5 " - -

Grid 03 1975 5 15.0 1.0 "

16.2 1.3 "

0.1 0.1 Tran 07 1972-74 2 15.5 .7 18.0 1.4 - -

Tran 07 1975 0 - - - - - -

Nov.- G Dec. All Sites 1972-74 4 Liver 13.4 4.5 Kidney 17.0 1.8 L "9 0.3 0.1 All Sites 1975 6 15.3 4.2 " 17.5 1.8 Boges 0.1 0.1 Grid 03 1972-74 2 17.0 2.8 18.5 0.7 0.2 0.0 Grid 03 1975 1 17.0 0.0 "

19.0 0.0 "

0.1 0.0 Tran 07 1972-74 0 - - - - - -

Tran 07 1975 2 13.5 2.1 "

19.0 0.0 "

0.2 0.1 9 Nov. All Sites 1974 3 Liver 12.9 5.4 Kidney 16.7 2.1 s

0.3 0.1 9

l e

9 9

I 177 Table 5. Zinc (Zn)concentrationsinMicrotusochrogaster(pg/g). i 1

Month Group N Tissue I S.D. Tissue I S.D.

June All Sites 1972-74 11 Liver 86.7 26.3 Kidney 84.3 19.6

> All Sites 1975 9 102.0 9.0 "

76.2 7.5 Grid 03 1972-74 5 83.2 14.2 90.4 28.0 Grid 03 1975 2 98.0 2.8 75.5 13.4 Tran 07 1972-74 5 83.4 34.9 80.6 8.6 Tran 07 1975 4 102.0 12.4 73.0 7.3

) Sept. All Sites 1972-74 6 Liver 105.0 13.8 Kidney 87.2 6.2 All Sites 1975 7 104.7 12.2 96.8 24.5 Grid 03 1972-74 3 96.7 11.7 83.0 2.7 Grid 03 1975 5 100.6 6.1 87.2 4.4 Tran 07 1972-74 2 110.0 14.1 "

88.5 5.0 Tran 07 1975 0 - - - -

)

Nov.-

Dec. All Sites 1972-74 ~4 Liver 87.0 21 . 5 Kidney 86.3 2.2 All Sites 1975 6 96.0 12.8 89.3 24.2 Grid 03 1972-74 2 97.0 18.4 85.5 3.5 Grid 03 1975 1 91 .0 0.0 52.0 0.0

) Tran 07 1972-74 0 - -

Tran 07 1975 2 106.0 19.8 112.0 21 .2 Nov. All Sites 1974 3 Liver 88.0 26.2 Kidney 87.3 0.58

)

)

)

)

)

178 (?

Table 6. Lead (Pb) concentrations in Microtus ochrogaster (pg/g).

O Month Group N Tissue I' S.D. Tissue s' S.D. Ti ssue I' S.D.

June All Sites 1972-74 11 Liver 0.3 0.2 Kidney 1.5 1.8 Pel t 0.2 0.2 All Sites 1975 9 0.3 0.1 1.1 0.9 0.4 0.3 gy Grid 03 1972-74 5 0.2 0.2 2.0 2.7 0.2 0.1 Grid 03 1975 2 0.3 0.1 1.6 1.3 0.6 0.2 Tran 07 1972-74 5 0.3 0.2 1.0 0.5 2.2 0.2 Tran 07 1975 4 0.2 0.1 "

0.7 0.6 0.2 0.1 Sept. All Sites 1972-74 6 Liver 0.3 0.1 Kidney 2.5 1.1 Pel" t 0.1 0.1 gp All Sites 1975 7 0.2 0.1 1.5 2.8 0.4 0.3 Grid 03 1972-74 3 0.2 0.2 3.2 1.2 0.2 0.1 Grid 03 1975 5 0.2 0.1 0.6 0.4 0.4 0.3 Tran 07 1972-74 2 0.3 0.1 2.1 0.1 0.1 0.0 Tran 07 1975 0 - - - - - -

Nov.-

Dec. All Sites 1972-74 4 Liver 0.6 0.3 Kidney 4.3 2.5 Pel t 0.4 0.2 All Sites 1975 6 0.6 0.3 2.8 3.3 0.5 0.4 Grid 03 1972-74 2 0.7 0.1 4.6 3.0 0.4 0.0 Grid 03 1975 1 0.6 0.0 1.2 0.0 0.5 0.0 Tran 07 1972-74 0 - - - -

gg Tran 07 1975 2 1.3 0.1 1.3 1.0 - -

Nov. All Sites 1974 3 Liver 0.5 0.3 Kidney 4.9 2.7 Pel t 0.3 0.3 O

O 9

O O

O 179.

Few seasonal or yearly differences in heavy metal concentrations were 8 observed (Tables 4 through 6). The only significant seasonal differences were the higher concentrations of lead in liver that occurred in November 1974 and November 1975 when compared to the June 1975 and 8 September 1975 samples respectively; the June 1975 zinc concentrations in kidney tissue that were lower than those observed in November 1974 or September 1975;and,the June 1975 lead concentrations in kidney tissue D that were lower than those observed in kidneys from November 1974. Lead concentrations were higher in November than earlier in the year. The few significant yearly differences were the high June 1975 kidney copper 3 concentrations for all trapping areas and for Transect 7 when compared to the composite 1972-1974 results, the high Grid 3 lead concentrations in kidneys during September 1975 as compared to the composite 1972-74 g results, and the low concentrations of lead in September 1975 pelts when compared to those of 1972-74 animals.

Adequate numbers of measurements have been made in Microtus tissues, g given the inherent seasonal and yearly variability of such measurements, so that reasonable comparisons to baseline conditions can be determined.

In order to detennine how baseline levels of heavy metals from animals on the PSC property compared to other animals studied, we com-g pared concentrations of both zinc and lead in prairie vole kidneys col-lected from 1972-76 to the few values in the literature. The only data we found suitable for comparison were for gray squirrels trapped in the Gulf Hammock Wildlife Management Area of Florida (a relatively undisturbed area) and Jacksonville, Florida, with some degree of industrial pollution (McKinnon, et al. ,1976, J. Wildl . Disease, 12:367-371). Kidneys from voles caught near the St. Vrain Nuclear Generating Station had higher O

180 L concentrations of zinc and lead than did the kidneys from squirrels col-O lected in rural Florida but less than the kidneys from squirrels exposed to light tc medium levels of industrial pollution in urban Jacksonville (T6ble 7, Figures 3 and 4). At this point, it is not evident why zinc and lead are found in higher concentrations in kidneys of voles from the O PSC property than in those of squirrels from rural Florida other than species differences. However, the levels of zinc and lead in kidneys of voles from St. Vrain are considerably lower than levels of kidneys of S squirrels from urban Jacksonville. If the St. Vrain f:uclear Generating Station becomes a significant producer of airborne or aquatic heavy metal contaminants, which enter or are deposited on plants, the levels of heavy 9 metals in vole kidneys should rise toward the levels observed in the kidneys of urban squirrels.

Amphibians were usually collected from Goosequill Pond or the ditch G draining into it so comparisons were only made between years and species.

The differences in mean concentrations of liver zinc in laboratory frogs (Rana pipiens) supplied by a commercial dealer, when compared with either e Woodhouse's toads (Bufo woodhouseii) or spadefoot toads (Scaphiopus bombifrons) from PSC property, were significant as were the mean copper concentrations in the liver of spadefoot toads when compared with Wood- e house's toads or the laboratory R. pipiens (Table 8). The yearly differences in the means of metal concentrations of liver copper and zinc in Woodhouse's toads also were tested for significance (Table 9). g The copper and zinc content of livers from Woodhouse's toads captured in 1975 were significantly lower than the contents found in 1973 and 1974 which are not different from one another. We do not know the reason for g these lower levels but suspect they are the result of rainfall and e

Table 7. Kidney concentratio9s of zinc and lead in gray squirrels

~a captured in Florida and in prairie voles captured at the Fort St. Vrain Nuclear Generating Station, Colorado.

Number Zinc 3 Lead 3 Groups Mean:S.E.

Animals Mean:S.E.

J ,

Jacksonville (souirrels)2

<1 year 75 27.72:1.21 1.32 0.17 1 year 69 29.68:1.80 1.28:0.24 2 years 20 30.54:2.49 1.1820.31 J 3 years 10 25.99:3.14 0.47:0.16 4 years 6 23.04:2.69 0.86:0.33 Gulf Haranock (souirrels)

, 1 year 5 14.32 1.64 0.20:0.02 J 2 years 7 18.61 1.43 0.26:0.04 St. Vrain (voles)

All animals 70 22.36:0.56 0.56:0.15 D Grid 3 33 22.79:0.96 0.64 0.12 Transect 7 16 21.81:0.93 0.41:0.11 IFrom McKinnon, et al., 1976.

D 2 Equals animals of different age classes.

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184 L Taole 8. Metal concentrations in amphibia (ug/g).

O Animal Group Analysis Tissue N Y S.D.

BBf Cu Liver 10 153 92.5 S3 3

1973 Cu 10 45.3 41.3 e BW All years Cu 33 238.1 206.1 BW 1972 Cu 3 233.3 118.46 BW 1973 Cu 11 328.2* 304.9 BW 1974 Cu 10 245.0 130.8 BW 1975 Cu 10 119 65.5 9

88 ---

Zn 9 217.8 132.6 SB 1973 Zn 10 117.3 24.6 BW All Years Zn 33 121.9 40.8 BW 1972 Zn 3 13.3 15.3 BW 1973 Zn 10 142 37.1 BW 1974 Zn 9 137.8 47.5 g BW 1975 Zn 10 100.4 29.0 BB ---

Zn Whole 10 129.0 22.8 Body BW All years Zn Whole 10 133.4 27.7 e Body I

BB are samples of tissue from commercial frogs (Rana pioiens) used to work out analysis techniques.

SB are samoles of tissue from Scaphiopus bombifrons, the spadefoot toad, from the Fort Saint Vrain Farm Pond. Samples were taken in 1973.

BW are samples of tissue from Bufo woodhousei, Woodhouse's toad from the Fort Saint Vrain Farm Pond. Samples were taken in 1972, 1973, 1974 and 1975. e 9

9 9

J 185 Table 9. Heavy metal concentrations in Bufo Woodhousei (pg/g).

3 Group Metal Tissue N I S.D. Tissue N 1 S.D.

1972 Cu liver 3 233.3 118.5 -- -- -- --

1973 Cu liver 10 351.0 311.3 -- -- -- --

3 1974 Cu liver 10 245.0 130.7 -- -- -- --

1975 Cu liver 10 119.6 65.5 kidney 10 13.8 4.7 1972-75 Cu liver 33 229.0 204.6 kidney 10 13.8 4. 7 1976 Cu liver 8 66.8 89.9 kidney 8 5.2 1.5 1972 Zn liver 3 93.3 15.3 -- -- -- --

'D 1973 Zn liver 10 142.0 37.1 -- -- -- --

1974 In liver 10 132.0 48.0 -- -- -- --

1975 Zn liver 10 100.4 29.0 kidney 10 93.8 16.6 1972-75 Zn liver 33 122.0 40.8 kidney 10 93.8 16.6 1976 Zn liver 8 83.6 7.4 kidney 8 82.4 13.0 D

D D

3 D

O O

186 O collecting patterns. In 1973 and 1974, rainfall was scattered in the Spring and pools of water were readily available to toads for breeding. 9 Thus, we simply collected during May when we could make time for such collections. In 1975 Spring rainfall was sparse and we could not collect toads easily. Therefore, we concentrated our collecting efforts following 9 what little rain there was. Thus, the animals were probably inhabiting more bodies of water in 1975 with lower levels of metal concentrations than in 1973 and 1974. It is encouraging, for baseline information, to O note that when rains are scatterod and the available ponds receive fresh water infrequently, there is no difference in year-to-year liver zinc and copper content in Woodhouse's toad. We also note that there are real e species differences in liver copper content (compare 1973 Spadefood toads with Woodhouse's toads, Table 8). Scaphiopus is a more opportunistic breeder than Bufo and may come out to breed only following rains when g ponds have low metal concentrations. Thus, it is interesting to note that Scaphiopus liver copper content is lower than Bufo. However, liver zinc contents do not differ; thus, suggesting that the two species g concentrate these heavy metals differently.

TRENDS, ENVIRONMENTAL QUALITY AND INFLUENCE OF THE STATION 9

As indicated in the Results and Discussion section, there have been a few changes in the vertebrate component of the environment surrounding the Fort St. Vrain Nuclear Generating Station. Most of the changes seen e in the past 7b years can be ascribed to or associated with climate or agricultural practices and none by direct link to effects of the Nuclear Generating Station. e, 9

Y 187 i

Over the 7h year inventory and monitoring period there have been no 3 obvious changes in species presence nor habitat use patterns by reptiles or by large mammals, except for beaver. Initially beaver were present

! in low numbers and minor activity. However, with a continuous and moni-h tored outflow of water from Goosequill Pond their activity became localized in the pond effluent stream flow area.

Small mamal populations have shown more fluctuations. It has p app *ared that most of these fluctuations were associated with various l

l agricultural practices, particularly those related to irrigation. When

! Grid 1 was allowed to go to the old field condition, ground squirrel lJ numbers were reduced and prairie voles increased. The burning of the field reduced the voles and allowed deer mice to incre'ase. The bulldozing and burning of weeds east of the fence and along the irrigation ditch on

'O Transect 4 in the Spring of 1974 resulted in the reduction of the popula-tions of deer and house mice. The channelization of the Goosequill Ditch along Transect 7 several times was coincident with a decline in voles lg and a rise in jumping mice. Flooding of the south ends of Grid 3 and i

Transect 5 by irrigation water runoff from neighboring fields preceeded declines in the numbers of voles captured in those areas.

3 Indeed, prairie voles (Microtus ochrogaster) were initially present on our sampling areas in fair numbers but since 1975 have been caught only in low densities. Likewise, deer mice (Peromyscus maniculatus)

g numbers have decreased through the years from their initial high densities but have been stable since 1976. There have been periodic irruptions of harvest mice and jumping mice but in both cases these seem to be related to weather and agricultural practices. Prairie dog (Cynomys ludovicianus)

O 188 towns have periodically been poisoned and hence greatly reduced temporarily 9

in numbers, but have always recovered. And lastly, ground squirrels are the only species which seem to have disappeared from the environment.

Such fluctuations have given rise to discussion about whether sampling e

areas should be protected from all activities. The area was historically agricultural before the Nuclear Generating Station was built. The chan-nelization of irrigation ditches, burning of weeds, poisoning prairie dog O

towns, etc., are all traditional agricultural practices and are part of the " environment." To leave areas unattended by man does not mean they will not change. Natural succession along unburned irrigation ditches O

and in old fields would, in itself, bring about changes in species com-position. Allowing prairie dog towns to increase without the natural predators that were present 100 years ago (e.g., black-footed ferrets) would also be somewhat " artificial." Thus, since the goal for the area seemed to be to maintain agriculture as previously pursued and not to establish a " natural" wildlife park without human intervention, the con-tinuance of nonnal agricultural practices and the fluctuations they cause

• seemed the more " natural" course to follow.

The species presence of breeding amphibians and their apparent relative densities have varied from year to year depending upon tempera- O ture and moisture conditions. The only obvious trends have been: (1) the 1

appearance of leopard frogs (Rana pipiens) in 1977. Given several years of no sightings and now several years with sightings becoming more frequent, 8 I conclude they are a new addition and not a species missed in the inven-tory phase. However, I cannot correlate their appearance with any obvious environmental change as all other amphibian species are still present and #

61 i

189-l were breeding in good numbers in Spring 1979. (2) Spiny soft-shelled p- (T.-ionyx spiniferus) and snapping turtles (Chelydra serpentina)do not now I

seem as abundant in the rivers -as in the early years of the study. But, again, this downward trend in numbers does not seem to be correlated with D

any obvious changes in the environment, especially due to the operation of the Generating Station.

l g)NITORING PROGRAM 3

Ef fectiveness l

l l It is difficult to conclude how effective an environmental monitoring

• program is. If effective means that the program measures well those fac-tors that have been affected by operation of the Nuclear Generating Station, then it is difficult to conclude that the program (or any monitoring pro-O gram) has been effective. The major problem here is in not being absolutely certain, a_ priori, what environmental influences a given modification (e.g., establishing a Nuclear Generating Station) will have. Indeed, if (O anyone could definitively answer such questions, we would not need moni-l toring programs. However, if effective means--does the program measure those parameters it is designed to measure--then I can conclude that Q monitoring has been effective in measuring species presence and certain population parameters. Since the ultimate effect of a modification on l these animals should affect these parameters, then we have an index to whether the populations have been adversely or beneficially affec ad.

lC

! The major disadvantage of the monitoring program is that it simply l

notes when and whether species are showing population declines and/or .

1

O local extinction. We do not have good measures of causations, except 1

0

190 C

for tF.e heavy metal analyses, but rather they must be sought as we see O

numbers changing. However, this is a problem comon to vertebrate moni-toring. By sampling more often (monthly or bimonthly) we could follow population trends better, determine if numbers were changing because of O

mortality or natality factors, and have a closer coupling of number changes to weather, agricultural practices and variations in operation of the Nuclear Generating Station. However, such sampling would be O

extremely expensive and probably economically unwarranted.

O C

O O

O O

0;

1 l

,0 191 O

O TERRESTRIAL INVERTEBRATES O

O O

by J. Wayne Brewer and

-o Judy Bodenham O

O O

O

O 192 INTRODUCTION Operation of the Fort St. Vrain Nuclear Generating Station could O' create environmental changes that would alter populations or biological cycles of terrestrial invertebrates in the area. According to previous reports (1, 2) the minor increases in radiation levels expected near the S Station probably would not affect most invertebrates. However, hot water discharged from cooling towers into man-made or natural drainage systems could affect them since studies have shown many species of inver- G tebrates to be sensitive to even minor changes in temperature (3, 7, 8).

An inventory of invertebrate species was conducted near the Station and six groups representing different ecological habitats were selected for 9 monitoring from 1972 through 1979. This report presents a summary and analysis of the data collected on those groups.

O METHODS A description of the study area was presented in an earlier report (4). The location of pit fall trap rows 2, 3 and 4 is shown in Figure 1 (row I was abandoned early in the study). Details of the procedures used have been presented previously (4), however, the following changes have since occurred: In January,1974 the Malaise trap was discontinued for diurnal invertebrates when it was destroyed by a storm. It was felt that the data obtained did not justify replacement cost. In January, 1975 the sampling period was changec from weekly to monthly intervals. It seemed O

reasonable that the large data base available made it possible to monitor populations adequately with reduced sampling periods. In January, 1976, Ms. Bodenham assumed responsibility for identification of the Formicidae O

when the services of Dr. Snelling were no longer available. Beginning January,1979 the black light trap was not established during the winter because reduced activity at that time made collection unnecessary.

O

) 193 1

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) Figure 1. Fo'rt St. Vrain Nuclear Generating Station and environs, showing. invertebrate collection sites.

)

194 RESULTS AND ANALYSIS Collembola O A list of the species of Collembola collected from three rows of pit fall traps naar the Fort St. Vrain Nuclear Generating Station site and serviced from 1972 until 1979 is presented in Table 1. The distri-O bution of Collembola was quite uniform in that all species were col-lected at all three of the sampling sites located at varying distances from the Generating Station. Population levels of the different species e

varied considerably during the study but that seemed to be primarily a function of natural population fluctuations. Species diversity of Collembola in the area was analyzed using Sorenson's quotient of simi-O larity (5). The procedure for calculating this similarity index has been previously reported (4). The similarity index for two areas having id.entical species composition would be 1.000. The index for two O

areas in which only 50% of the species were found in both situations would be 0.500. We compared species collected each year to all years to detemine if species composition of the area changed over the O

course of the study. As shown in Table 2, the similarity quotient for all yearly comparisons was high, ranging from 0.928 (1973 versus 1975) to 1.000 (several couplets). This indicated that the species composition of Collembola did not vary substantially from 1972 to 1979.

Since the Nuclear Generating Station was partially operational at various times beginning about 1976, these results suggest that the operation periods did not adversely affect species composition in the areas surrounding the Station. We also compared total collections from all years from the three different sampling sites as shown in O

O'

1 4D 195 1

Table 1. Species of Collembola collected from pit fall traps at the q, Fort St. Vrain Nuclear Generating Station Site, Platteville, Colorado, 1972-1979.

4p Collembola Entomobryidae Entomobrya nivalis (L.)

1 Entomobrya unostrigata Stach Entomobryoides guthriei (Mills)

Lepidocyrtus cyaneus Tullberg gp Tomocerus vulgaris (Tullberg)

F.ypogastruridae Hypogastrura armata (Nicolet) gp Hypogastrura matura (Folsom)

Isotomidae Isotomurus palustris (Muller) 7;-) Proisotoma minuta (Tullberg)

Pseudachorutes subcrassoides (Mills)

Pseudosinella rolfsi Mills 3

Sminthuridae Bourletiella arvalis (Fitch)

Sminthurinus elegans (Fitch)

Sminthurides pumulis (Krausberger)

-)

Xenylla sp.

t i

1 l

1

?

1

'E 196 Table 2. Matrix of Sorenson's quotient of similarity comparing species composition of Collembola collected in the environs of the Fort St. 9 Vrain Nuclear Generating Station by year from 1972-1979.

R R R R R R R 9

$ $ $ $ 2 S S S 1972 -

1.000 .965 .928 .965 1.000 .965 .965 1973 -

.965 .928 .965 1.000 .965 .965 ,

1974 -

.952 1.000 .965 1.000 1.000 1975 -

.962 .928 .962 .962 1976 -

.965 1.000 1.000 ,

1977 -

.965 .965 1978 -

1.000 1979 -

Table 3. Matrix of Sorenson's quotient of similarity comparing species composition of Collembola collected in the environs of the Fort St. O Vrain Nuclear Generating Stakjon by pit fall trap row.

m m w ,

5 5 $

e e e Row 2 -

.965 .965 Row 3 -

1.000 g Row 4 -

9 9

l

I U 197 i

l Table 3. The results indicate that the species composition of those h areas was similar over the seven years of the study with quotients

?

i of similarity ranging from 1.000 to 0.965.

- Annual variations in populations of Collembola collected from pit O fall traps are presented in Figure- 2. Mean monthly collections of Collembola were over 60,000 individuals in 1973 but declined to a low of slightly more than 9,000 in 1975. Thereafter, populations generally O increased and remained at approximately the 1973 levels for 1977 and 1978. A comparison of numbers of Collembola from the three.

rows of pit fall traps is presented in Figure 3. It is evident the O number of individuals collected varted considerably from the three areas sampled during the study. Collections from Row two, the sample site located furthest from the plant, were low compared to Rows three O and four, which were much closer to the Generating Station. General population trends, however, were similar from all three areas, with the exception that populations around Row three did not recover from

,0 the 1975 low as quickly as populations from Rows two and four.

As with species composition, it appeared that population levels of Collembola in the general environs of the Nuclear Generating Station l

l.3 have not beec affected adversely by operation of the Station. Present population leveis and species composition are now comparable to those occurring in the area at the beginning of the study.

.g -

l

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198 9

100,000 -

o  :

@ 50,000 -

P  :

p 20000 -

g H

10,000 --

3 D

_o 5000 b -

E -

$ 2000 - 8 1000 1973 1974 1975 1976 1977 1978 Date Figure 2. Total number of Collembola collected from pit fall traps near the O Fort St. Vrain Nuclear Generating Station. Platteville. Colorado. 1973-1979.

O 100,000--.

50.000 }

~

Row 4 0

, 20,000 -

Row 3 75 a 10,000 --

D 5000 -

?

o 2000 L

2 1000 -

E  :

3 500 }

_ e 200 -

100 ' ' ' ' ' i 1973 1974 1975 1976 1977 1978 Date e

Figure 3. Number of Collembola collected from pit fall traps near the Fort St. Vrain Nuclear Generating Station. Platteville. Colorado. 1973-1979.

e

O 199 Fonnicidae O A list of the species of Formicidae collected in the vicinity of the Nuclear Generating Station during this period is presented in Table

4. Species distribution varied for the three areas but most species.

O were comon to all areas.

Annual variations in population levels of Formicidae collected from all three rows of traps is presented in Figure 4. Populations were O low in 1973 and 1974 but began a general increase in 1975 that continued, with minor exceptions, to a peak in 1979. A comparison of collections from th6 individual sample areas is presented in Figure 5. As with the

'O Coliembola there wc: ncima in the number of individuals collected from the different areas. Population levels were highest from Row two, the area most distant from the Station. In general, trends

O in population shifts were similar in collections from the three areas.

An exception was in the collections for 1979 where numbers dacreased slightly from Row 3, and drastically for Row 4 but increased greatly

g for Row 2. Since Rows 3 and 4 are much closer to the Generating Station than Row 2, and thus should be more affected by any environmental changes produced by its operation, it is possible that the population declines g observed from those areas were related to increased activity of the Station in 1977 and.1978 Population changes in biological systems are rarely imediate. It is possible that the above changes are lagging influences of earlier environmental effects Caused by operation of the Station. Such changes could be caused by various interrelated environ-mental factors such as an increase in temperature or humidity, a modifi-m cation of vegetation composition, an altered food chain, or a modified v.

trophic level response which in turn create invertebrate stresses.

l lO

0 200 Table 4. Species of Formicidae collected from pit fall traps at the Fort St. Vrain Nuclear Generatin9 Station site, Platteville, Colorado, 9l 1972-1979.

Formicidae O Formicinae Lasius latipes (Walsh)

Caii.ponotus nearcticus Emery 8 Camponotus sayi Emery CamponotusvicinusMayr Formica bradleyi Wheeler #

Formica fusca Linne Formica lasioides Emery Formica limata Wheeler #

Formica cinerea lepida Wheeler Formica neoclara Emery Formica neogagates Emery 9 Formica perpilosa Wheeler Formica subnuba Emery Lasius niger neoniger Emery 9 Lasius pallitarsis (Provancher)

Polyergus breviceps Emery l

_ Formica obscuripes Forel e

, Formica pallidefulva nitidiventris Emery Lasius murphyi Forel Lasius interjectus Mayr 3 9

• 201 Table 4. (Cont.) l l

Dolichoderinae Dorymyrmex pyramicus (Roger)

Tapinoma sessile (Say) {

Myrmicinae Myrmica brevinodis Emery Myrmica brevispinosa Wheeler Myrmica sabuleti americana Weber Pheidole pilifera coloradensis Emery Pheidole bicarinata Mayr Pogonomynnex_ occidentalis (Cresson)

J Solenopsis molesta validiuscula Emery Stenamma brevicorne Mayr Ponerinae

^)

Ponera trigona opacior Forel D

D D

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l 10,000 --

3 5000 m -

5 g 2000 -

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e g 1000 --

L ".

R 500 -

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10 0 1973 1974 1975 1976 1977 1978 1979 Date g Figure 4. Total number of Famicidae collected from pit fall traps near the Fort St. Vrain Nuclear Generating Station, Platteville, Colorado, 1973-1979.

5000 -

4 2000 -

2 1000 m --

N 2 g

5-j 500 C

H -

o 200'- Row 3 e 8 o Row 4 i

Z i

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1973 1974 1975 1976 1977 ~978 1979 Date g Figure S. Number of Fomicidae collected from pit fall traps near the Fort St. Vrain Nuclear Generating Station, Platteville, Colorado, 1973-1973.

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D 203 Silpha ramosa D_ Biological studies showed that both adult and immature carrion

. beetles feed on dead animal carcasses, mainly small rodents (4). Conse-quently, this insect was considered important to the study because of D its high level in the food chain and the possibility of biological

, magnification of changes caused by operation of the Station. Population t

levels of adult and immature forms of S. ramesa collected during the 3 study are shown in Figure 6. The number of adults remained relatively l constant with peak levels occurring in 1975 followed by a slow decline through 1978 and a resurgence in 1979. Population levels of the immature j forms followed a similar pattern but with levels fluctuating more than those of the adults. The data from 1979 indicated that populations were increasing and that the declines seen earlier were probably a result of natural variatica rather than an influence of operation of the Generating

! Station.

I Data on collections of S. ramosa adults from the three areas sampled by pit fall traps are presented in Figure 7 and similar data on the innatures are shown in Figure 8. Both forms were collected in high num-bers throughout the study from rows three and four but infrequently from

_ row two. Since populations were consistently highest from row three J

(Figures 7 and 8), and that is the row most likely influenced by hot water discharge (4), it seems unlikely that S_. ramosa populations are being adversely affected by operation of the Station. Thus, data on J,

general population levels and those collected from specific areas indicated that populations of this species have not been reduced by operation of the Station.

O

204 C

100 -

O

$2 80 - Immatures

?

2 y 60 -

s e 15 e 40 -

h Adults z 20 -

g O

1973 1974 1975 1976 19 77 1978 1979 Dat* '

Figure 6. Mean nunber of Silpha ramosa collecud per month from pit fall traps $

near the Fort St. Vrain Nuclear Generating Station. Platteville. Colorado.

1973-1979.

O 40 -

2 co o e j 30 -

5 C

H

_ 20 -

o E Row 3

• D 10 E

/ Row 4 a

i z

' ' l I  ! I O 1 Row 2 1973 1974 1975 1976 1977 1978 1979 O

Date Figure 7. Mean ntsnber of Silpha ramosa collected cer month from pit fall traps near the Fort St. Vrain Nuclear Generating Station. Platteville. Colorado.

1973-1979. (Adult form.)

6 1

9

O 205

)

J 3 10 0 -

fa 80 -

E

, 2 J p 60 -

H Row 3 o

c. 40 -

o D

D h Row 4 z 20 -

O I i i  ! I I Row 2 '

1973 1974 1975 1976 1977 1978 1979

] Date Figure 8. Mean neber of Silpha ramosa collected per month from pit fall traps near the Fort St. Vrain Nuclear Generating Station. Platteville. Colorado 1973-1979. (Innature form.)

J a

h

206 Araneida T5e number of Araneida (spiders) collected during the study is pre- O sented in cigure 9. Population levels varied considerably in the area beginning with relatively low levels in 1973 and reaching a peak in 1975 followed by a consistent decline through 1976,1977,1978 and 1979. 8 Thus, it is evident that r,opulation levels in the vicinity of the Generating Station have been reduced since 1975. It is not possible to determine the reason for the decline from our studies but it seems S correlated with increased activity of the Generating Station. We must note, however, that even after several years of declining populations the levels are still comparable to those at the beginning of the study. G A comparison of collections from the three sample areas is pre-sented in Figure 10. Collections from Row two, which is located at the greatest distance from the Station, followed the general trend of total G collections discussed above. However, collections from Rows three and four varied and the population declines were less severe. Collections from Row four showed numbers increased from 1977 to 1978 with a moderate g decline in 1979. Population levels fr>m area three declined from 1977 until 1978, then increased slightly in 1979.

Consequently, although the general populations of Araneida are g declining in the vicinity of the Station, the data from individual sample areas suggest the cause is probably not due to the operation of the Station, since collections from the areas most immediate to it do not g

follow the general trend.

O O

m, _ _ .

O~ 207 400 -

350 -

i m

3 y300 -

i3 O

p _ 250 o

L e

D 200 -

E

a

'Z O 150 -

O 1973 1974 1975 1976 1977 1978 1974

, Date J

l Figure 9. Mean number of Araneida collected per month from pit fall traps near the Fort St. Vrain Nuclear Generating Station. Platteville. Colorado. 1973 .979.

l 16 0 -

'O 14 0 -

120 -

O m ca

$100 - "#

/

G 80 -

O o _ -Row 3 L

o a 60 -

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z

9 40 -

l Row 2 20 -

O I ' I  ! ' ' '

O 1973 1974 1975 1976 1977 1978 1979 Date Figure 10. A comparison of collections of mean number of Araneida from the three l

sample areas near Fort St. Vrain Nuclear Generating Station. Platteville. Colorado.

1973-1979.

O

208 Tricoptera Tricoptera, or caddisflies, are nocturnal, aerial invertebrates that were collected in large numbers in a black light trap during the study. The maximum number of individuals collected per month for the years 1973 through 1979 is presented in Figure 11. Population levels

• were high in 1973, declined in 1974 and 1975, increased slightly in 1976 and 1977 and remained stable in 1978 and 1979.

Population levels of Tricoptera vary and it appears likely that the O observed changes in numbers were a result of natural fluctuations. For example, the low levels in 1975 may be a result of the lower than normal moisture levels that occurred that year. However, the fact remains that

• the population has declined since the beginning of the study and although increased numbers nave been collected in recent years, levels are still below those at the beginning of the study. Since the immature stages of 8 this organism are aquatic, they could be affected by changes in water temperature caused by the hot water discharge t,y the Station. For example, Fey (7) demonstrated that increased temperature of a river caused by a #

power station eliminated the quiescent stage of one species of Tricoptera and advanced emergence time three to four months. Earlier, Nebeker (8) showed that premature emergence could eliminate species if air tempera- 9 tures were lethal, as would be the case for Tricoptera during winter months. It cannot be demonstrated that the decline in numbers of Tri-coptera was due to the operation of the Station, and in fact, numbers 9 have increased somewhat from 1975 until 1979, a period when time of Station operation generally increased. Population levels have not approached those at the beginning of the study; however, and it is pos- e sible that the reduced numbers are a result of changes caused by the Station.

O

'3 209 l

l 9

10,0COc-5000 -

. .)

2000 -

9 $ 1000 -

ca -

m -

2 -

$c 5CO -

H

~) _

o 3

200 -

D E

a z 100 --

D  :

50 -

'D 20 -

r  ! i I I I i 10 1973 1974 1975 1976 1977 1978 1979 Date J

Figure 11. Maximum number of Tricoptera collected per month from a black light trap located near the Fort St. Vrain Nuclear Generating Station, Platteville, Colorado, 1973-1979.

D n i l

l l

210 C" Heteroceridae The heterocerids, or mud-loving beetles, live in the mud shores of GD the slough near the Generating Station. The maximum number of beetles collected in the black light trap per month for the years 1973 through 1979 is presented in Figure 12. Population levels of this beetle declined ED from a high in 1973 to a low in 1975, similar to the trend in Tricoptera populations previously discussed. However, beginning in 1976, population levels increased about to the 1973 levels. In 1978 and 1979 population ED levels were somewhat lower than in previous years, but higher than the low of 1975. Thus, it appears that the fluctuations in population levels of heterocerids is not correlated with operation of the Station but rather q>

is the result of natural factors. For example, it is likely that a major factor causing the low populations recorded in 1975 was the low moistore level that occurred during that year, as discussed for the Tricoptera. as ap '

9 9

l l

Ol 9

i i

i

'O 211 b

O-1 t

O-10,000 _ -

5000 -

!O 20C0 -

iO 3m 3000 _

2 v -

5 E 500 -

d -

O -

O j y 200 -

a

E 2

z 100 -

to  :

4 50 -

1

!O 20 -

' ' ' ' '  ! l 10 1979 1973 1974 1975 1976 1977 1978 Date

.g

' Figure 12. Maximum number of Heteroceridae collected per month from a black light trap located near the Fort St. Vrain Nuclear Generating Station. Platte-ville. Colorado. 1973-1979.

i

!O 1 0

21 2 C

SUM 4ARY 9

population levels of terrestrial invertebrates collected in the environs of the Fort St. Vrain Nuclear Generating Station varied con-siderably during the study period of 1972 through 1979. However, the O

variation in population levels vf the six groups monitored durint that time seemed to be a result of natural fluctuations rather than operation of the Station. There are, however, two possible exceptions where 9

adverse influences to invartebrate populations might have resulted from operation of the Station. Firr.t, a general population increase of Fannicidae occurred during the latter stages of the study when collections O

from all areas were considered. However, a comparison of the individual sampling areas near the Station revealed a decline in numbers of individ-uals. The population decline was minor from row three, the site con-9 sidered most likely to be influenced by heated discharge water, but greater from row four where the effect should be less serious, If the ns, ' ion in numbers of Formicidae was due to the operation of the Station, the opposite situation would be expected. We believe that the population decline in the area near the Station could have resulted from natural factors and not Station operation but it is not possible to rule out the latter possibility.  %

• The second possible exception was in collections of Tricoptera where population levels declined compared to those at the beginning of the study. The Tricoptera is the group most likely to be affected by O heated discharge water because the imature forms live directly in the water of the slough, and possibly, that of the concrete-lined drainage l ditch. Thus, the population reduction of Tricoptera might be a direct Oi O!

% 21 3 result of the operation of the Generating Station. Some evidence to-the

) contrary is that populations of heterocerid beetles followed the "mid-study" decline similar to that of Tricoptera but have since recovered .to levels approximating those early in the study. Since these beetles live

) in the mud shores of the slough the effects of the heated discharge water would be less dramatic' than for Tricoptera, but the similarity in popula-l tion trends suggests that the fluctuations might be natural ones. Also, O population changes in Tricoptera are known to fluctuate widely in natural situations and it seems probable the changes seen during this study were i

natural ones.

O In general', we believe that the limited operation of the Fort St.

l_ Vrain Nuclear Generating Station to date has not caused changes in species l composition nor population levels of terrestrial invertebrates' considered 3 in this study. In our opinion, construction of the Generating Station, and the loss of former suitable terrestrial invertebrate habitat in the area, have had more serious effects on the terrestrial invertebrate 9- populations than the operation of the plant. Certainly, construction of a ten-story building with acres of parking lots and associated facilities is a drastic change from a fomer prairie environment.

3 The benefits of the monitoring program have been excellent. The monitoring provided a rare op portunity to follow changes in populations of terrestrial invertebrate species over an extended period of time.

l sg __

l l

!D . )

i l l

O 214 REFERENCES (1) Skaife, S. H. 1968. Experitients on the effects of radiation on ,

ants. Australian Natural History. March:27-28.

(21 Cadwell, L. L. , and F. W. Whicker. 1972. The arthropod community.

h Radioecology of Some Natural Organisms and Systems in ,

Colorado. Tenth Annual Report on Atomic Energy Commission Contract. (Available from Department of Radiology and Radiation Biology, Colorado State University, Fort Collins, Colo. 80523). ,

84 pp.

(3) Wurtz, C. B. 1969. The effects of heated discharge on freshwater benthos. h Biological Aspects of Thermal Pollution. Krenkel, ,.

P. A. , and F. L. Parkers, Eds. , Vanderbilt University Press, Nashville, Tenn. 199 pp.

(4) Brewer, J. W. 1976. Terrestrial invertebrates. h A Biological Survey of Fort St. Vrain Nuclear Generating Station Site.

Thorne Ecological Institute, Boulder, Colorado. 138 pp.

(5) Southwood, T. R. E. 1966. Ecological Methods. London. 391 pp.

O (6) Wur. der, B. A. Personal comunication. Department of Zoology and Entomology, Colorado State University, Fort Collins, Colo.

80523.

9 (7) Fey, J. M. 1977. Die Aufheizung eines Mittelgebirgsflusses und ihre Auswirkungen auf die Zoozonose-dargestellt, an de Lenne (Sauerland),

Arch. Hydrobiol. Supp. 53:307-363. (original not seen, cited by 9

Ward and Stanford 1980. In: The Ecology of Regulated Streams, pp. 35-55.)

(8) Nebeker, A. V. 1977. Effect of high winter water temperatures on O

emergence of aquatic insects. Water Research. 5:777-783.

O

g-3lS C-O C

C lI13BV1083 3I130 C

C O

i

,O i

'O t

O k

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

O 216 LITERATURE CITED ,

Glover, F. A. 1976. A biological survey of Fort St. Vrein Nuclear Generating Station Site. Thorne Ecological Institute, Boulder, ,

Colo. 138pp.

9 9

O O

9 3

S.

1

'i; .

_.