ML19210D939

Responds to Request for Addl Info in 780526 IE Insp Repts 50-458/78-04 & 50-459/79-04.Forwards La State Univ 790731 Status Rept Re Environ Study of Culvert Crossing Alligator Bayou

ML19210D939
Person / Time
Site:	River Bend
Issue date:	07/31/1979
From:	Weigand J GULF STATES UTILITIES CO.
To:	Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
RBG-6612, NUDOCS 7911290061
Download: ML19210D939 (5)

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July 31, 1979 RBG - 6612 File G9.5 Mr. W. C. Seidle, Chief Reactor Construction and Engineering Support Branch U. S. Nuclear Regulatory Cecmission, Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011

Dear Mr. Seidle:

River Bend Station - Units 1 & 2 Docket Nos. 50 h58, 50 k59 Gulf States Utilities (GSU) offers the following status report concerning the environmental study of the culvert crossing of Alligator Baycu. This is submitted in partial fulfillment of additional information required in your inspection report 50 h58/h59 Oh dated May 26, 1976. Since July 1978 GSU has received five quarterly ecological narrative reports from our censultant, Louisiana State University (LSU). The su= mary of each of these reports did not identify any conclusive short-term er long-term environmental impact associated with the culvert crossing.

Attached to this letter is a recent su==ary of the LSU monitoring effort to date. This su mary critiques the last year's effortc and makes recernendatf.cns for future =cnitoring activities.

As a result of recent consultations with LSU, it is not deemed necessary at this time to instigate any mitigating action.

f-Sincerely, h

• WMf 26 J. G. Weigand Gene *al Manager - Nuclear Projects Attachments

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LOUISI AN A STATE UNIVERSITY AN D A G RIC U LTU R AL A N D M ECh ANICAL COLLEGE B ATO N R O U GE . t O UI S'I A N A . 70803 Center for A ricultural Sciences And Rural Development LO utS?A?.A AGRICULTURAL EXPERIMENT STATION

• • J.UMcTUU"l O

' " " ' ' ' " " July 31, 1979 Mr. James E. Booker Gulf States Utilities Company P.O. Box 2951 Beaumont, Texas 77704

Dear Mr. Booker:

At the request of Bill Reed of your licensing division, this letter w'111 su==arize our progress on the special floodplain studies of the LSU Phase II Intt.im Ecological Monitoring Progra= at the River Bend site. It will also address various problems we have encountered during the first 14-16 months of sampling and document changes in our procedures that we feel are justified.

The basta objective of our floodplain studies is to evaluate the aquatic environmental effects of the earthen fill and 12-culvert configuration for the river access road crossing of Alligator Bayou. Two major, interrelated issues are being considered: (1) whether or not covements of fishes along Alligator Bayou and the floodplain are significantly hindered and (2) the extent to which spawning and/or nursery habitats are affected. As noted in earlier correspondence and discussions, both of these issues are clouded by the lack of extensive baseline data from the floodplain in its unaltered condition. That is, no matter how detailed our present observations may be we can never be sure what they mean in terms of the preconstruction situation.

It is possible, nevertheless, to obtain sece information that will enable us to infer changes and assess their relative significance. Our approach toward gathering of sach infor=ation has involved three =ain thrusts:

a) Monitoring of changes in fish population structure in Needle Lake with respect to successive periods of isolation or semi-isolation during low-water seasons, in hopes of recognizing additions / deletions tha could be attributed to its connection te the Mississippi River via lower Al. ligator Bayou and Thompson Creek times of backwater encroach =ent.

b) Periodic sa=pling of the river access road culverts to detect the actual passage of fishes.

c) Intensive sa=pling of adults and young-of-the-year of fishes on opposite sides of the river access road during vernal high-water periods to evaluate possible differences.

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. .' J . E. Booker Jyly 31, 1979 Page 2 Virtually nothing has been accc=plished with respect to item (a) for two principal reasons. Throughout =ost of the low-water period of semi-isolation in 1978 we did not have op(rational pulsating DC electrofishing equip =ent. Even so, access to Needle lake was (and re=ains) inadequate for the trailering in of the necessary equipment. The major difficulties with the existing road (jeep trail) into Needle Lake are its narrowness and several sharp turns. An i= proved rurface would definitely enhance the usefulness of the road but is not crucial except perhaps during excessively wet weather. At any rate,. it is our understanding that sufficient widening and straightening of the road will not be possible due to objections raised by the terrestrial ecology consultant. We therefore have resolved to abandon our efforts to monitor fish population changes'in Needle Lake in favor of intensified sampling of larval and early juvenile fishes. This decision is further justified by another, essentially overriding, factor -- namely, the increased tendency for overbank flooding into and out of the river above Needle Lake. Migratory routes for fishes to and from Needle Lake now seem unlikely to be confined to lower Alligator Bayou except in relatively unusual water years.

Sampling in the access road culverts has been frustrated by the irregular configuration of their =ouths on opposite sides and, especially, by the relatively brief periods (in Springs of 1978 and 1979) when stages / flows were apprcpriate for the use of hoopnets in the apertures. Opportunities were missed altogether in 1979 but we managed to make three overnight sets in April-May of 1978. These, observations, which each consisted of two nets fishing " upstream" and two nets fishing " downstream" (i.e., 4 culverts on a given set), indicated at least some cove =ent in either direction by a few species of fishes. A few bowfin, carp, and gizzard shad were caught moving " upstream," whereas.even fewer bowfin, gizzard shad, and river carpsucker were recorded as =oving " downstream." Of the fishes moving " upstream," so=e of the shad and the single carp were running-ripe

, individuals. That is, they were specimens in spawning condition that could be interpreted as being involved in migration for purposes of reproduction. Thus one preli=inary conclusion seems justified: The culverts do not completely inhibit movements of some species which are known to be migratory (gizzard shad, carp).

Givea the appropriate hydrographic conditions in Spring 1980 ve plan to intensify the culvert conitorin, efforts to derive a better understanding of the qualitative and quantitative aspects of fish passage.

Another approach to the evaluation of fish passage is the marking or tagging and release of speci= ens above and below the access road. The greater the nu=ber of

=arked fish released and recaptures obtained, regardless of the position of the recaptures, the = ore infor=ation we will have to assess the relative significance of culvert passages or lack of the same. With the availability of our electro-fishing equipment in Spring 1979 we were able to =ake nu=erous (weekly or more f requent) atte= pts to mark / release fishes above and below the access road.

Unfortunately, throughout =ost of the season stages were so excessively high that fishes had various routes in addition to the culverts for traversing the access road. The prolonged high stages also tended to disperse adult fishes to the.

extent that electrofishing was relatively unproductive. Only several dozens of fishes other than shad (which are too fragile for tagging) were caught, as opposed to the hundreds or even thousands for which we had hoped. Even so, evo recaptures were recorded. One was a black crappie that was released south of the road and recaptured in the sa=e place on the folloiing visit; the other was a flathead catfish released north of the road and caught several days later in the

=ain river channel near Port Hudson (roughly 8 miles downstream). As in the case of direct sa=pling in the culverts we plan to greatly intensify = ark / release

} d I, $ !2 t

,. J. E. Booker J.ul.y 31, 1979 Fage 3 activities during the high-water period of 1980.

Sampling for assessment of relative abundance of adult fishes on opposite sides of the access road was acco=plished to a limited extent in 1978 (primari1f due to lack of equip =ent). Much greater intensity of effort was possible in 1979. Some of the sa=ples from the latter year are as yet unprocessed, but the general results are that =arkedly greater numbers of fishes were taken per unit of effort below the access road. This was especially true earlier during each high-water period, when opposite sides of the access road were more effectively isolated.

There also tended to be more kinds of fishes on the south side of the road, and the increased diversity was largely attributable to the occurrence of species with main river channel affinities (e.g. , shortnose gar, skipjack herring, big =outh buffalo, blue catfish, white bass, striped mullet). A possible inference here, of course, is that the relative concentrations of fishes below the access road represent a piling up, or " traffic jam," of individuals attempting to traverse the road. On the other hand, the concentrations might merely reflect a tendency for the fishes to be attracted to localized areas of relative turbulence.

Floodplain samples of young-of-the-year fishes from Spring and early Sum =er 1979 are, for the most part, unprocessed as of this writing, but the results from 1978 offer some insights. Again, there tended te be greater relative abundance and diversity below the access road. Of particular importance was the disparity in apparent densities (in favor of the south side) of larval and early juvenile buffalosuckers, which are =ajor co=mercial fishes in the river. Tb4s could mean that reproductive succcss for these suckers was greater below the access road, either in terms of more intensive spawning or perhaps a greater rate of survival.

As in the case of adult fishes, however, these observed concentrations might

=erely reflect th3 influence of some overriding physical f actor (s) . For example, the cor.centrations of young near the southern apertures of the culverts could represent a preponderance of individuals that were recently flushed through from the north side. In future high-water spawning seasons we plan to intensify our sampling efforts for young fishes in floodplain habitats, both in and near the culverts as well as in the far-field, in an attempt to compile more relevant information. ,

Routine sa=pling of larval and early juvenile fishes in Needle Lake indicated that in both 1978 and 1979 it was used to only a limited extent as a spawning area by fishes other than its normal inhabitats. Inasmuch as overbank flooding afforded direct access to Needle Lake from the river in both years it might be inferred that this swa=p area is of marginal value as spawning habitat for riverine fishes, regardless of any influences of the access road on migrations.

This concept has relatively profound implications in ter=s of our basic objective, so we have decided to intensify sa=pling of larval and early juvenile fishes in Needle Lake by means of more frequent visits, additional stations, and supple-mental gears. For this reason we still would appreciate any effort that is possible tc improve vehicular access to Needle Lake.

In su==ary, we have the following preliminary indications from two high-water seasons of special floodplain studies:

a) At least some movement by certain species of fishes occurs in both directions through the secess road culverts.

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, ,. J . E. Booker July 31, 1979 Page 4 b) Relative abundance and diversity of adult fishes tend to be greater on the south (" downstream") side of the river access road, especially during the tarlier phases of backwater encroach =ent, when the culverts cre the only means of traversing the road. The differentes seem largely attributable to fishes of main river channel affit.ities.

c) Relative abundance and diversity of young fishes, especially those resident as adults in the river, tends to be greater on the couth side of the river access road.

d) The swa=p area known as Needle Lake se' ems to receive only limited use as a spawning site by =igratory riverine fishes, even when direct access is afforded by exceptionally high flood stages.

On balance, the above lead us to the highly speculative conclusion that the river access road crossing of Alligator Bayou does have some inhibitory influence on fish covements and associated aspects of their reproductive ecology but that these effects cay not have as great a negative significance as we had- thought possible. Perhaps more importantly, we feel that these observations and the experience gained through their co=pilation have better defined the strategy needed for future sa=pling.

Sincerely yours, Oh-John V. Conner, Ph.D.

Principal Investigator cc: Bill Reed, GSU Beau =ont Joe Leazines, GSU River Bend Mark Walten, CSU River Bend JVC/cf

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