compensation) does not generally rear its challenging head until one
is dealing with population projections (Van Winkle 2000). The “apples” on
the ecosystem/community limb of the tree represent assessment methods
that are “maturing” but that are generally viewed as not being sufficiently
“ripe” at present to be useful for decision making. In this way, the tree also
helps answer questions relating to complexity and realism versus usefulness.
Retrospective methods use data collected at a site to evaluate the
character, function, quality, and/or integrity of the water body and/or to
evaluate whether or not a change in a population/community/ecosystem
has occurred that may be related to the operation of the power plant (EPRI
1999) (see Figure 3.3). These methods are best applied to assess changes as
a result of power-plant operation at facilities that have been operating for
several years. Thus, the methods are most applicable for existing facilities
rather than for new facilities. However, monitoring and other studies at
existing facilities during the past three decades have resulted in large
databases that provide a perspective and valuable guidance for assessing
the impacts of entrainment and impingement at new facilities (e.g., Mayhew
et al. 2000).
Site specificity explains why so many modeling approaches have developed for the same, relatively uncomplicated, issue of mortality resulting
from entrainment and impingement. Several factors contribute to this
history of site-specific assessments and decision making. Each assessment
of entrainment and impingement tends to involve unique features because
each ecosystem is unique with respect to its fish species and hydraulic and
water-quality characteristics. Technology choices also are site specific. For
example, a Gunderboom cannot be used where there are strong currents
or heavy natural-debris loads. In addition, the industry, decision makers, and
stakeholders (and their social or institutional constraints) tend to be site
specific and unique. A consequence from a regulatory perspective is that a
simple model and approximate data may be adequate for one 316(b) assessment, while another superficially similar situation may require morecomplex models and additional data. It is also counterproductive to make
regulators and others force-fit their knowledge into a predefined mold to
maintain the appearance of uniform and fair regulations.
If site specificity is as important as we believe, then industries, regulators,
and stakeholders faced with overly rigid 316(b) rules may be forced to
codify into approved formats their understanding of the factors influencing
the impacts of entrainment and impingement at their unique site. Or, an
overly conservative approach (e.g., making dry cooling towers the BTA)
may also be a convenient way to evade assessing 316(b) impacts, including
the negative impacts of efficiency penalties and increased use of fossil
resources. Such “conservatism” may be just shifting concerns from the
entrainment and impingement of fish to concerns about energy costs,
increased use of fossil fuels, and environmental impacts of alternative
energy technologies.
3. Modeling Fish Entrainment and Impingement Impacts
59
is dealing with population projections (Van Winkle 2000). The “apples” on
the ecosystem/community limb of the tree represent assessment methods
that are “maturing” but that are generally viewed as not being sufficiently
“ripe” at present to be useful for decision making. In this way, the tree also
helps answer questions relating to complexity and realism versus usefulness.
Retrospective methods use data collected at a site to evaluate the
character, function, quality, and/or integrity of the water body and/or to
evaluate whether or not a change in a population/community/ecosystem
has occurred that may be related to the operation of the power plant (EPRI
1999) (see Figure 3.3). These methods are best applied to assess changes as
a result of power-plant operation at facilities that have been operating for
several years. Thus, the methods are most applicable for existing facilities
rather than for new facilities. However, monitoring and other studies at
existing facilities during the past three decades have resulted in large
databases that provide a perspective and valuable guidance for assessing
the impacts of entrainment and impingement at new facilities (e.g., Mayhew
et al. 2000).
Site specificity explains why so many modeling approaches have developed for the same, relatively uncomplicated, issue of mortality resulting
from entrainment and impingement. Several factors contribute to this
history of site-specific assessments and decision making. Each assessment
of entrainment and impingement tends to involve unique features because
each ecosystem is unique with respect to its fish species and hydraulic and
water-quality characteristics. Technology choices also are site specific. For
example, a Gunderboom cannot be used where there are strong currents
or heavy natural-debris loads. In addition, the industry, decision makers, and
stakeholders (and their social or institutional constraints) tend to be site
specific and unique. A consequence from a regulatory perspective is that a
simple model and approximate data may be adequate for one 316(b) assessment, while another superficially similar situation may require morecomplex models and additional data. It is also counterproductive to make
regulators and others force-fit their knowledge into a predefined mold to
maintain the appearance of uniform and fair regulations.
If site specificity is as important as we believe, then industries, regulators,
and stakeholders faced with overly rigid 316(b) rules may be forced to
codify into approved formats their understanding of the factors influencing
the impacts of entrainment and impingement at their unique site. Or, an
overly conservative approach (e.g., making dry cooling towers the BTA)
may also be a convenient way to evade assessing 316(b) impacts, including
the negative impacts of efficiency penalties and increased use of fossil
resources. Such “conservatism” may be just shifting concerns from the
entrainment and impingement of fish to concerns about energy costs,
increased use of fossil fuels, and environmental impacts of alternative
energy technologies.
3. Modeling Fish Entrainment and Impingement Impacts
59