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Section 5 Formulation of Alternative Plans

EAA Storage Reservoirs Revised Draft PIR and EIS February 2006

5-38

for all the performance measures used. The uncertainty regarding the ability of

SFWMM to show differences among alternatives may be found in the Risk and

Uncertainty section. After examining the model output, the Ecological Sub-team

decided upon a final subset of nine performance measures that best encompasses

and reflects project objectives to quantify ecological output. These system-wide

performance measures are quantifiable, predictive, and possess environmental

outputs capable of evaluating differences and benefits between alternatives.

They have the greatest potential of being used in the alternative evaluation and

selection process. Table 5-14 displays the performance measures, associated

targets, and the associated project objectives. Detailed information regarding

performance measure descriptions, targets, justifications, current conditions,

and evaluation methods may be found in the RET performance measure

documentation sheets (USACE, 2004b).

Besides the RECOVER performance measures, two other performance measures

were developed to capture water quality benefits to the lake and the greater

everglades: backpumping volume to Lake Okeechobee and STA bypass volume,

respectively. The target for both of these performance measures is to minimize

the volume of water that is backpumped to the lake and the volume of water

that bypasses STA-3/4.

5.4.2.1.4 Predictive Evaluation Tools and Operational Assumptions

Like many other CERP projects, the Natural Systems Model (NSM) has been

used to characterize pre-drainage conditions in the Project area. The operational

assumptions used as input into the SFWMM runs include the current WSE for

Lake Okeechobee regarding regulatory releases from the lake. For the existing

and future without project conditions, the water from the lake regulatory

releases is sent to tide through the St. Lucie and Caloosahatchee Estuaries, and

runoff water from the agricultural area is released to the WCAs.

For the with project condition, once the lake stage goes higher than a certain

stage, water is released first to the reservoirs (cell 2); if the lake stage continues

to go beyond an upper limit stage, then water would be released to tide.

As the reservoir stage increases in response to receiving water from Lake

Okeechobee and/or from surrounding agricultural runoff, it is possible to

intentionally deliver water to downstream natural areas via STA-3/4 in response

to downstream environmental demands, or to local agricultural stakeholders to

help meet water supply demands that would otherwise be met via deliveries of

water from the regional water management system. In addition to planned

releases, it is anticipated that there will be periods during which releases from

the reservoir will be necessary to maintain reservoir stages at safe/acceptable

levels and/or in preparation for storm events. As a guiding principle, it is

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