Performance Indicators (PI's) are listed in attached tables.   Each matrix contains values for 24 potential PI's and 5 Alternatives (50Base, ALT-A, ALT-B, ALT-C,  ALT-D, & ALT-D13R).   A separate PI matrix is supplied for each BMP performance assumption:

• 25% load reduction = ECP design basis
• 51% load reduction = average observed EAA Basin load reduction in Water Years 1995-1997

Performance indicators are grouped in four general categories:

• Phosphorus Concentration Criteria
• Phosphorus Load Criteria
• Hydrologic Criteria
• Settlement Agreement & Everglades Forever Act Criteria

Values in the first three groups are based upon the entire simulation period for the Restudy (1965-1995).  Values in the last group are based upon Water Years 1979-1988, which was used for setting interim treatment goals under the Settlement Agreement and Everglades Forever Act.

The methodology used for ranking alternatives follows that suggested by Eric Bush of FDEP (e-mail to Restudy Water Quality group, May 13, 1998).   For each performance indicator, alternatives are ranked on a scale of 1 (worst) to 6 (best).  Composite rankings are developed within each category based upon a weighted average of ranks for each PI.  Weighted ranks are rescaled to a range of 1 to 10.   Each PI is assigned a weighting factor (>=0).  Weighting factors should be determined by group consensus.  Default values (1) are assumed for all but two PI's in this preliminary evaluation.   The two exceptions are outflow concentrations from STA-6; these are not influenced significantly by any of the Restudy alternatives.

An Excel workbook containing PI matrices and ranking methodologies is attached.  This workbook can be used by Restudy Water Quality Group members to test alternative weighting schemes.  No doubt there is room for simplification and consolidation of the PI's.  A PI can be eliminated from the ranking scheme by setting its weighting factor to 0.

Generally, differences among restudy alternatives based upon these criteria are relatively small.   Preliminary weighted scores (scale of 1-10) for each alternative and category using the 25% BMP performance assumption are summarized below:

Rankings with the 51% BMP performance assumption are similar.  The ranking scheme is not totally satisfactory because it does not reflect the fact that differences among alternatives are very small for many PI's.  For example, the range of 1965-1995 WCA inflow concentrations for Alternatives ABCDD13R is 55 to 58 ppb.   The range of 1965-1995 total load reductions is 167 to 169 mt/yr.  Greater differences are observed for other indicators (e.g., range of STA Bypass Loads =  4.9 to 7.1 mt/yr).   It may be appropriate to eliminate redundancy by eliminating some PI's or by adjusting weighting factors. 

Although the differences in PI values are relatively small, the high ranking of Alt-A reflects the following factors:

• Lower bypass volume for STA-2 (4.4 kac-ft/yr for Alt-A vs. 7.6-7.9 kac-ft/yr for Alts-BCDD13R)

• Lower bypass volume for STA-34 (19.9 kac-ft/yr for Alt-A vs. 27.7-28.2 kac-ft/yr for Alts-BCDD13R)

• Higher runoff volumes from the S5A basin into STA-1W under Alts-D& D13R (181 kac-ft/yr vs. 168-169 kac-ft/yr for Alts A-C); this is thought to reflect impoundment influences.

Click here to view Performance Indicator Values & Rankings of Alternatives

Click here to download Excel Workbook for Ranking Alternatives

Selected Charts & Discussion (attached to this page):

Phosphorus Concentration Criteria:

• WCA Inflow Phosphorus Concentrations
• Refuge Inflow Phosphorus Concentrations
• STA Outflow Phosphorus Concentrations, 25% BMP Reduction
• STA Outflow Phosphorus Concentrations, 51% BMP Reduction

Phosphorus Load Criteria:

• WCA Phosphorus Loads
• Refuge Phosphorus Loads
• STA Bypass Loads
• LEC Water Supply Delivered Through WCA's
• Total WCA Load with Concentration > 50 ppb
• Total Load Reductions in STA's & Reservoirs

Hydrologic Criteria:

• WCA Inflow Volumes
• Refuge Inflow Volumes

Settlement Agreement & Everglades Forever Act Targets:

• WCA Inflow Phosphorus Concentrations, WY 1979-1988
• Refuge Inflow Phosphorus Concentration, WY 1979-1988
• STA Bypass Loads, WY 1979-1988
• WCA Flow Increase, WY 1979-1988