“minimize.” As discussed below, either a general definition can be provided, or a process can be suggested to define the site-specific AEI. In
either case, modeling plays a central role in linking scientific knowledge
to a value-laden decision-making framework. A theme of this paper
is to identify numerous choices possible in building this science–policy
bridge.
The U.S. Environmental Protection Agency (EPA) published 316(b)
assessment guidelines in 1977 that were remanded in court because of
procedural issues. Nonetheless, state regulators essentially followed the
unofficial guidelines into the 1990s, with several hundred assessments of
entrainment and impingement performed during the 1970s and 1980s. In
the absence of EPA regulations clearly defining AEI, BTA, or an assessment process, state and federal permitting authorities produced their
own definitions on a case-by-case basis, relying on past decisions, administrative findings, scientific advances, and site-specific considerations. Several
recent papers trace the history of 316(b) assessments (Anderson and
Gotting 2001; Dey et al. 2000; May and van Rossum 1995; Nagle and
Morgan 2000).
Renewed interest in 316(b) assessments has been triggered by a 1995
consent decree that establishes a timetable for EPA to propose and take
final action with respect to addressing impacts from existing and new
CWISs. The EPA recently proposed a draft tiered regulatory approach for
its 316(b) rule making (Nagle and Morgan 2000). Tier 1 requires performing a screening analysis to determine the potential for impacts from entrainment and impingement. Tier 2 requires a characterization of uses and
biological status of the source water body to determine the potential for
AEI from entrainment and impingement. Tier 3 requires studies to quantify impacts from entrainment and impingement and to determine the
appropriate BTA. Modeling of impacts from entrainment and impingement
likely would be a component of 316(b) assessments only for those CWISs
requiring Tier 3 evaluations. This paper applies to facilities with such
CWISs.
The potential impacts of 316(b) regulatory controls on economics,
electricity reliability, and the environment are far from trivial (Veil 2000).
Consequently, there is renewed interest in the science underlying assessments of entrainment and impingement, including constructive roles that
can be played by modeling. This chapter presents a forward-looking strategy about the central role of modeling in decision making involving impact
assessments on fish. An example success story is summarized in Sidebar 3.1.
Other modeling successes are detailed in Barnthouse (2000) and Lorda et
al. (2000).
Modeling is considered here in the broader context of value-laden decision making. “Value” refers here to specific management goals, management objectives, endpoints, measures, and decision criteria. (See Sidebar 3.2
for definitions and examples.) We describe two roles for modeling, and
3. Modeling Fish Entrainment and Impingement Impacts
47
either case, modeling plays a central role in linking scientific knowledge
to a value-laden decision-making framework. A theme of this paper
is to identify numerous choices possible in building this science–policy
bridge.
The U.S. Environmental Protection Agency (EPA) published 316(b)
assessment guidelines in 1977 that were remanded in court because of
procedural issues. Nonetheless, state regulators essentially followed the
unofficial guidelines into the 1990s, with several hundred assessments of
entrainment and impingement performed during the 1970s and 1980s. In
the absence of EPA regulations clearly defining AEI, BTA, or an assessment process, state and federal permitting authorities produced their
own definitions on a case-by-case basis, relying on past decisions, administrative findings, scientific advances, and site-specific considerations. Several
recent papers trace the history of 316(b) assessments (Anderson and
Gotting 2001; Dey et al. 2000; May and van Rossum 1995; Nagle and
Morgan 2000).
Renewed interest in 316(b) assessments has been triggered by a 1995
consent decree that establishes a timetable for EPA to propose and take
final action with respect to addressing impacts from existing and new
CWISs. The EPA recently proposed a draft tiered regulatory approach for
its 316(b) rule making (Nagle and Morgan 2000). Tier 1 requires performing a screening analysis to determine the potential for impacts from entrainment and impingement. Tier 2 requires a characterization of uses and
biological status of the source water body to determine the potential for
AEI from entrainment and impingement. Tier 3 requires studies to quantify impacts from entrainment and impingement and to determine the
appropriate BTA. Modeling of impacts from entrainment and impingement
likely would be a component of 316(b) assessments only for those CWISs
requiring Tier 3 evaluations. This paper applies to facilities with such
CWISs.
The potential impacts of 316(b) regulatory controls on economics,
electricity reliability, and the environment are far from trivial (Veil 2000).
Consequently, there is renewed interest in the science underlying assessments of entrainment and impingement, including constructive roles that
can be played by modeling. This chapter presents a forward-looking strategy about the central role of modeling in decision making involving impact
assessments on fish. An example success story is summarized in Sidebar 3.1.
Other modeling successes are detailed in Barnthouse (2000) and Lorda et
al. (2000).
Modeling is considered here in the broader context of value-laden decision making. “Value” refers here to specific management goals, management objectives, endpoints, measures, and decision criteria. (See Sidebar 3.2
for definitions and examples.) We describe two roles for modeling, and
3. Modeling Fish Entrainment and Impingement Impacts
47