water intake For it to be more realistic, total ecosystem effects must be considered, rather than j u s t numbers of aquatic organisms impinged or entrained, according t o three electric power company scientists
Ibrahim H. Zeitoun John A. Gulvas John J. Rochow Consurviers Power Conzpany Jackson, Mich. 49201
Electric utilities that use the nation’s waters for power plant operation should recognize pertinent federal, state, and local water quality regulations. In Michigan, for instance, the Federal Water Pollution Control Act amendments of 1972 ( F W P C A ) , the Clean Water Act amendments of 1977, and the S t a t e Water Quality Standards establish the principal regulatory framework controlling water use. For the operation of a power plant, Section 3 16(b) of Public Law 92-500 ( F W P C A ) requires that the intake structure, location, design, construction, and capacity reflect the best available technology (BAT) for minimizing adverse environmental impact. T h e cooling water withdrawal is associated with two fundamental biological impacts: impingement and entrainment. Impingement refers to those organisms trapped against the intake screen, whereas entrainment applies to aquatic organisms smaller than screen openings, which pass through with the cooling water. From a biologist’s viewpoint, the statutory language of Section 3 16(b) recognizes that intake impact assessp e n t should be related to its total effect on the ecological system, not solely on the numbers or weights of aquatic 398
organisms impinged or entrained. The lack of emphasis on this aspect i n the FWPCA and the lack of an established set of criteria to explain or define acceptable limits of environmental inipact creates perplexing situations which have resulted in polarization and frustration among water users and regulatory agencies. Resiliency In natural systems, it is essential to recognize that there are potentials that can be utilized and limits not to be exceeded. Also, it is imperative to recognize and to accept the fact that man’s activities always will be associated with environmental changes. Therefore, regulators have to integrate a system‘s potentials and limits into policy making. For instance. they should recall that biological systems a r e resilient and that a system‘s ability to withstand perturbations is certainly dependent on its present health and on the extent of imposed stress. The mechanism of resiliency via self-rep I ace men t is oft e n ca I 1ed b i o I og i ca I compensation or ecosystem stabilit). In Michigan, it has often been expressed that any resource losses a t power-generating facilities, even if ecologically insignificant, are considered a s significant losses to the state’s natural resources. This viewpoint is inconsistent with the ecological understanding of the language of Section 316(b) and is contradictory to ecological fundamentals. Furthermore, it is scientifically inadequate to quantify the degree of impact to a n aquatic ecosystem by relying only on im-
pi n g e 171en t a n d en t ra in men t data, because ecosystem resiliency is not considered. As a result of this limited ecological understanding, more stringent 1 imitations on power plant operation may be imposed, and may be harsher in one state than in another. However, stringent limitations that d o not take into account the ecosystem, from a holistic viev.point. are not justified a s long a s the plant operation is not causing an adverse impact to the ecological system. In addition, more stringent limitations in one state are often associated with more economic burdens and restraints on utilities and consumers v.ithin the state. It has been argued that limiting water use through the use of cooling towers reflects BAT as indicated in Section 316(b) of the FWPCA. This may be correct under certain circumstances. Recent studies, however. have demonstrated that the mechanicaldraft cooling towers a t the Palisades Uuclear Plant, which is located on the eastern shore of Lake Michigan, have ;I significant adverse impact on terrestrial habitats in the immediate vicinit) of the plant. For example, several acres of healthy forest vegetation were destroyed by excessive icing and deposition of chemicals added to the cooling water. Under these circums t a n ccs, various reg u 1a tors, in their interpretation of the Federal Water Pollution Control Act. failed to consider the anticipated impacts of plant operation on other iniportant segments of the environment. Eco I og i ca 1 i m pac t assess men t ,
0013-936X/80/09 14-0398$0 1.OO/O @ 1980 American Chemical Society
therefore, should be addressed from a holistic standpoint. T h a t is, alternate cooling schemes must be evaluated as to their effects on all ecosystems. ACceptability of an intake, according to the criterion of the extent of resource losses, should be based on prediction or detection of significant adverse changes or disruption a t the ecosystem level. Too often, regulators have become overzealous by placing unrealistic restraints on impingement and entrainment a t the expense of total ecosystem health. Some effects ignored Furthermore, in many cases, power plant effects are isolated and the effects which other stresses impose on aquatic life are ignored. Meteorological, physical, and chemical changes, as well as point and nonpoint source effects on the aquatic environment, must be recognized. T h e annual die-off of alewife in the Great Lakes because of natural changesin water temperature is a good example of the inability of this well-known sensitive species to cope with naturally occurring, as opposed to artificially induced, changes in temperature. Thus, alewife impingement d a t a reported for power plants on the Great Lakes probably are exaggerated, since alewife collected on the screens a r e already stressed; their losses are not entirely the result of power plant operation. Recently, regulatory agencies have recommended that Consumer Power Company’s J.H. Campbell Plant intake for Units 1 and 2 be relocated to an offshore location in Lake Michigan. T h e plant derives its cooling water from Lake Michigan via a dredged intake through the eutrophic Pigeon Lake. Regulatory agencies maintain that this intake has potential adverse impact on the indigenous aquatic life in Pigeon Lake. Their recommended intake location, they claim, will restore Pigeon Lake’s biotic community to its previous state. It is true that Pigeon Lake was altered by the introduction of Lake Michigan oligotrophic water. T h e situation, in fact, significantly enhanced aesthetic and recreation values and water quality in Pigeon Lake. T h e mixing of Lake Michigan water with the eutrophic Pigeon Lake water has preserved the integrity of Pigeon Lake. Furthermore, extensive biological studies, conducted in 1977 and 1978 by the Great Lakes Research Division of the University of Michigan, conclusively indicated the absence of deleterious effects on fish and benthic communities in Pigeon Lake. These studies gave evidence of the presence
Cooling tower drift. At nuclear power plant
Icing. Cooling tower impact on uegetation
Vegetation damage. Chemical and physical. from mechunical-dmft cooling towers Volume 14, Number 4, April 1980
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of large populations of native fish which are supported by a very rich supply of fish food organisms.
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