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HomeMy WebLinkAboutNC0000396_Biological Studies_19850201 •. 7 ') • • • •K r Ashevji•{, tAjj1\ State of North Carolina Department of Natural Resources and Community Development 512 North Salisbury Street • Raleigh, North Carolina 27611 James G. Martin, Governor S. Thomas Rhodes, Secretary Division of Environmental Management February 1, 1985 Mr. R. B. Starkey, Jr. Manager, Environmental Services Carolina Power and Light Company Shearon Harris Energy and Environmental Center Route 1, Box 327 Jew Hill , North Carolina 27562 Subject: Biological Studies Carolina Power and Light Co. Asheville Steam Electric Plant Buncombe County, "1.OV Dear F1r. Starkey: Your letter of December 17, 1984, detailing the results of biological studies in the cooling water impoundment of Asheville Steam Electric Plant (Lake Julian) , has been reviewed by staff members of this Division. As you are aware, conduct of these studies was a condition of NPDES Permit No. NC0000396 issued June 30, 1981, and were to demonstrate that Lake Julian remains a reasonable fishing resource in consideration of the Company's thermal discharge. In review of your recent report and previous results, it appears that the cooling water discharge to Lake Julian from the CP&L Asheville Steam Electric Plant has caused no drastic changes to the biota of these waters , and that a reasonable recreational fishery continues to be present. Therefore, no additional biological studies are necessary at this time. We will , however, reinstate the requirement if there is a clear indication of its need. If you have any questions, please contact Mr. Forrest R. Westall of our Asheville Regional Office at telephone number (704) 253-3341. Sincerely, ORf !NAL S(,_.;N:D BY t- R. Paul Wilms Acting Director ��� RPW:dm P.O.Box.7687,Raleigh,North Carolina 27611-7687 Telephone 919-733-4984 Vv An Equal Opportunity.attirmativeAction Employer • • ,s2„tfr_ CP&L — BUNCOMBE COUNTY rv` Carolina Power & Lig ht Company qy �/ Shearon Harris Energy & Environmental Center / Route 1. Box 327 New Hill. North Carolina 27562 DEC 17 1984 Serial: ESS-84-924 Mr. Roy Davis �•..a''1 N.C. DNR&CD Division of Environmental Management ' Interchange Building 159 Woodfin Street P.O. Box 370 !c, '- Asheville, North Ca' ILLItt D-4-1 Dear Mr. Westall: c4 Biolof 1 7= 1dant Biological st ctric Plant cooling impoundment) we �`' � with the program approved by the { ' lent. Sampling has been completed E I � anticipated for the remainder of the Samples cc ;, and data are being analyzed. Preli ins in the lake were physically and c :nthos, and zooplank- ton population , and it appears at this time that popultt,..,,__ 7-to-year variation. Discrete depth zooplankton sampling appe . indicate that during summer months, microcrustaceans migrate down through the water column to the vicinity of the thermocline (and exhibit diel vertical migrations) rather than disappear from the lake. Macroinvertebrate data do not indicate ele- vated concentrations in the deep 'bottom areas during summer but do indicate that populations of oligochaetes and tolerant chironomids are present. Food habit studies of tilapia indicate that the fish feed predominantly on diatoms and filamentous green and blue-green algae (during the winter collection period). Some benthic organisms and sediment were found in stomachs, but occurrence was irregular. No ichthyofauna were found in tilapia stomachs. Standing crop estimates from two coves in Lake Julian ranged from 4,565 to 32,020 fish per hectare. Weight varied from 59.8 to 203.9 kg/hectare. The average standing crop (table enclosed) was greater than many other reservoirs and species composition is similar to that reported in past years. The greatest changes in fish populations, as indicated by the • 0 Mr. Roy Davis 2 DEC 17 1984 standing crop estimates, were declines in blue tilapia and increases in threadfin shad. The decline in blue tilapia is probably the result of cold water temperatures in January that killed thousands of tilapia. The number and size of tilapia collected, however, indicate that they remain a dominant species in the lake and abundance is probably increasing. Largemouth bass averaged 120 fish weighing 5.8 kg/hectare, while bluegill averaged 3526 fish weighing 31.4 kg/hectare. These values indicate good populations relative to most other mountain lakes. The data necessary to make population estimates for large- mouth bass has been entered on the computer system, but no estimates are available yet. The preliminary creel survey data indicate that fishing pressure during spring was very high and that good catches of largemouth bass, bluegill, and channel catfish were made. There were catches of tilapia made during sum- mer indicating some fisherman utilization. Until all data are received, how- ever, no estimates can be made of fishing pressure or exploitation of the various fish species on an annual basis. With this information, it appears that no drastic changes have occurred to the biota of Lake Julian and that a reasonable recreational fishery con- tinues to exist. It will take several months following completion of sampling (December 1984) to completely analyze the data and produce a report. It is anticipated that such a report will be completed in early 1985 and submitted to you by May 1, 1985. Since biotic conditions are similar to previous years and specific anal- yses will not be available until 1985, CP&L plans no field studies to be con- ducted at Lake Julian next year. This will allow thorough analysis of the data and recommendation and review of management and/or monitoring activities for future years. We would be glad to discuss this proposal at your convenience or respond to any questions you may have. Yours very truly, R. B. Starkey, Jr Manager Environmental Services W H T/sbk Enclosure cc: Mr. R. B. Hamilton 6 f , y • • 411 Table 1 Density and standing crop estimates of fish collected by cove rotenone sampling at Lake Julian during 1984 (Coves A and 0 combined). Species Number/hectare Weight (kg)/hectare Threadfin shad 12,842 26.5 Unidentified bullhead 2 < 0.1 Brown bullhead 17 < 0.1 Channel catfish 64 4.8 Unidentified sunfish 31 0.1 Sunfish (hybrid) 7 0.1 Redbreast sunfish 1,068 8.5 Warmouth 176 0.4 Bluegill 3,526 31.4 Redear sunfish 7 0.8 Largemouth bass 120 5.8 Blue tilapia 431 53.4 Total 18,292 131.9