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Section 5 Formulation of Alternative Plans

EAA Storage Reservoirs Revised Draft PIR and EIS February 2006

5-41

TABLE 5-15: FRAMEWORK FOR ECOSYSTEM CONDITION BENCHMARKS

Score Condition

0.9-1.0 Fully restored

0.8-0.9 Mostly restored

0.6-0.8 Functional and sustainable

0.4-0.6 Minimally sustainable

0.2-0.4 Declining

0.01-0.2 Fully degraded

After each performance measure was quantified for a given ecological region, an

ecological benefits index was calculated for that region by aggregating the

performance measure values into an equation to produce a single ecological

benefits index value for the region. This provided a means for addressing non-

independence between performance measures and allowed a means for

weighting more important performance measures. The approach is similar to

what is used in the Hydrogeomorphic Method (HGM) for wetland assessment

models (Smith, et. al., 1995; Smith and Wakeley 2001). With HGM, these

equations are used to derive functional capacity indices for evaluating wetlands.

The same approach can be used to derive a single evaluation or benefits value

for a given alternative based on all of the performance measures applicable to a

given ecological region. By applying various mathematical functions to the

equation, the approach provides a means for addressing correlated performance

measures and adjusting performance measure weighting factors. Thus,

interactions that may exist between and among performance measures can be

addressed. The weighting factors applied are for descriptive purposes only, and

should not be construed as a final weighting. The same applies for how

correlated performance measures are handled. The justification for any and all

weighting that may be conducted in the analysis should be documented in detail.

Factors that should be considered when determining performance measure

weighting include uncertainty in hydrologic metrics, degree of development,

calibration, and validation of the PM, degree of justification based on the best

available scientific research, and importance of the PM as an indicator in

shaping the ecosystem.

The equation below provides an example for performance measures that apply to

Lake Okeechobee. If we assume that each is independent of one another, and all

are equally weighted, an ecological benefits index for the lake (EBILO) can be

calculated by aggregating the individual performance measures into an equation

as follows:

EBILO = (QILO-E3 + QILO -E10)/2

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