ML20215K630
| ML20215K630 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 12/31/1986 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML20215K614 | List: |
| References | |
| NUDOCS 8705110274 | |
| Download: ML20215K630 (7) | |
Text
ATTACIBEElff 1 CATAWBA NUCLEAR STATION ENVIRONMENTAL PROTECTION PLAN 1986 AERIAL REMOTE SENSING VEGETATIVE COMMUNITIES
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CATAWBA NUCLEAR STATION VEGETATION MONITORING 1987 INTRODUCTION The Catawba Nuclear Station Non-Radiological Environmental Protection Plan requires that the Catawba site be monitored for possible effects of cooling tower drift on vegetation due to operation of Catawba Units 1 and 2. This monitoring is to be accomplished beginning the first September following operation of Unit 1 and is to continue in alternate years for three monitoring periods following operation of Unit 2. Unit 1 generation began in January 1985. This report describes the results of the monitoring program for the period 1983 through 1986.
The Catawba Environmental Report (ER) indicated that the area within the NE and SW sectors approximately 950 feet from the center of the cooling tower yard would receive maximum drift deposition. Total dissolved solids (TDS) in the drift were pro-jected to be in the range of 350 to 500 mg/t, based on the influ-ent makeup water TDS of 60 mg/E and an operating range of 7 to 10 cycles of concentration.
Drift deposition rate calculations in the Catawba ER predict-ed total solids deposition rates of 2-3 kg/ha/ month (2-3 lb/ acre /
month) based on 350 to 500 mg/t of TDS in drift. The Catawba FES suggests that thresholds for visible leaf damage in some sensitive plants fall in the range of 10 to 20 kg/ha/ month (9 to 18 lb/ acre /
month). Since these thresholds exceeded the projected solids deposition rates by factors of approximately 5- to 10-fold, drift from the Catawba cooling towers was not expected to produce adverse impacts on site vegetation beyond the cooling tower yard or plant boundaries.
MATERIALS AND METHODS The condition of Catawba Nuclear Station site vegetation has been monitored by color infrared aerial photography, supplemented by ground level visual inspection of site vegetation. Aerial photography was performed in September 1983 and 1984 (preoperational), in September 1985 (first operational growing season), and in September 1986 (second operational growing season). Ground level observations were made in spring and summer 1986 and in early spring of 1987 to supplement observations based on aerial photography. The conclusions in this report are based on inspections of the IR photographs and ground level observations to date.
Aerial IR photography was obtained on 6 September 1983, on 2 September 1984, on 14 September 1985, and on 14 September 1986, using Kodak IR Type 2443 film at 1:6000 (1 in = 500 ft) scale.
Vegetation shown in the photographs within a radius of approxi-mately 1 km of the cooling tower yard was inspected for evidence of dead or damaged foliage which could be related to cooling tower operation, using information provided by Murtha (1972, 1984) as a guide.
RESULTS Operation of the Catawba cooling towers began in January 1985, but significant levels of operation relative to drift production and possible effects on vegetation did not occur until March-April and June-August 1985 (Tables 1 and 2). The towers first operated at a load producing maximal one-unit evaporative water loss during July and August 1985. Therefore, vegetation in the vicinity of the towers experienced drift deposition over much of the 1985 growing season (April-August) and during the 1986 growing season. Full scale operation of Unit 2 began in July-August and November-December 1986. Therefore, site vegeta-tation has not yet experienced drift deposition from full two-unit operation during the growing season.
Forested areas located within 1 km of the tower consist of mixed pine-hardwoods, loblolly pine plantations, mixed shortleaf-Virginia pine stands, and mixed hardwoods. These stands are described in Duke Power (1975).
Inspection of the IR photographs has not revealed any evi-donce of damage to vegetation in the vicinity of the cooling towers. Color variations apparent in the IR photographs are related to the differences in species composition among the vari-aus stands. The pine stands tend to present a darker magenta to bluish-magenta image due to shadowing caused by the elongated needles. Hardwood foliage is brighter magenta to purple-red due to the more extended reflective leaf surfaces (Murtha 1972). No evidence of dead foliage (yellowish images) or defoliated branches (green, blue, or silvery images) was apparent in IR photos through September 1986, nor do the variations in color images suggest the presence of living but physiologically damaged foliage (violet to bluish images). Color variations between stands of differing com-position, and within stands of a given composition, are consistent in appearance between the 1983, 1984, 1985 and 1986 photographs.
Therefore, the photographs do not suggest the presence of any progressive response of the vegetation to the influence of cooling tower drift as of September 1986.
Vegetation on areas within a 1-km radius of the cooling towers was inspected on the ground for evidence of drift damage in May and August, 1986. No evidence of drift damage to foliage was observed. Since the summer of 1986 was a period of extreme drought throughout the southeastern United States, some signs of accelerated leaf sensescence on broad-leaf species was evident in August. However, the vegetation within the postulated zone of influence of the cooling tower drift did not differ in this regard from that occurring on many sites elsewhere in the area. Mortality of some individual trees and shrubs might be expected due to drought effects. Such responses could be expected to become apparent during the 1987 observation period.
Inspection of the site in March 1987 revealed the presence of needle tip necrosis (browned or " scorched" needles) on loblolly pines along the north side of the cooling tower yard at a distance of approximately 200 feet from the nearest tower. Some browning needles was also seen on loblolly pines to the east of the yard, again with only the trees nearest the cooling towers affected.
These conditions were not seen in 1986. Although needle losses can be caused by ice storms or low temperatures, the localization of the response suggests a possible relationship to the Catawba cooling towers. It is noted that vegetation did not experience full-scale drift exposure from two-unit operation until December 1986, after the 1986 aerial photographs were taken in September.
It is possible that increased icing of trees near the towers is responsible for these conditions. Further observations will docu-ment any continuing abnormalities in vegetation near the Catawba cooling towers.
Table 1. Evaporative losses for Catawba Nuclear Station cooling towers, 1985 (millions of gallons, MG).
MONTH UNIT 1, MG January 26.64 February 32.58 March 247.09
. April 215.71 May 0.19 June 160.87 July 459.48 August 548.03 September 563.83 October 240.42 November 108.54 December 427.60 T
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Table'2. Evaporative losses for Catawba Nuclear Station cooling towers, 1986 (millions of gallons, MG).
MONTH UNIT 1, MG UNIT 2, MG January 455.1 -
February 518.4- -
March 462.1 -
April 524.1 -
May 492.9 -
June 97.1 -
July 322.0 48.2 August 71.2 395.3 September 0.0 0.0 October 0.0 0.0 November 159.0 149.0 December 547.4 620.0 i
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References Duke Power Company. 1975. Catawba Nuclear Station Terrestrial Studies (Submitted to U.S. Atomic Energy Commission Directorate of Licensing, January 31, 1975).
Murtha, P. A. 1972. A Guide to-Air Photo Interpretation of Forest Damage in Canada.- Canadian Forestry Service Publica-tion No. 1292. Canadian Forestry Service, Ottawa. 62 pp.
Murtha, P. A. 1984. Vegetation Damage Detection and Assessment:
The Photographic Approach. Pp. 337-354 in: Renewable Management Application of Remote Sensing. Proceedings of the RNRF Symposium on the Application of Remote Sensing to Resource Management, Seattle, Washington, American Society of Photogrammetry, Falls Church, VA.
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