Paleoecology Coupled with Salinity Models

A Synthesis of Linked Paleoecological and Regression Model Evaluations to Simulate Everglades Hydrology and Florida Bay Salinity Response for Restoration Performance Measures

Principal Investigator: Frank Marshall, Cetacean Logic Foundation

Collaborator: G. Lynn Wingard, USGS

Funding: USACOE RECOVER Branch, Susan K. Kemp

·    5 individual sediment cores from Florida Bay  were coupled with multiple linear regression models to estimate paleo-based hydrology and salinity

·    Results from each analysis were synthesized

·    Establishing the paleo-based salinity regime in Florida Bay requires about 2.5 times the current flow into Everglades National Park

·    The needed volume of water is available in the freshwater being discharged to tide


A primary goal of the Comprehensive Everglades Restoration Plan (CERP) is restoration of freshwater patterns delivered to Florida Bay resulting in a restored salinity regime.  Performance measures (PM) developed by RECOVER (Restoration Coordination & Verification) are based on a linked method using paleoecologic characterizations and multiple linear regression models to simulate upstream freshwater flow and stage from paleo-based estimates of salinity (Marshall et al, 2009).  In recent work, the system of models was improved to include the effects of sea level rise and non-linear relationships over the 36-year period of simulation.  The updated procedure was applied using cores from Whipray Basin, Rankin Lake, Russell Bank, Little Madeira Bay, and Crocodile Point.  The model outputs were synthesized using Optimal Linear Combiners into a combined estimate of stage and flow needed to produce the synthesized paleo-based salinity.  When the results are interpreted, the combined paleo-based flows in Shark River and Taylor Sloughs are about 2.5-3 times and 3.5-4 times the average existing flow, respectively.  The paleo-based increase in Shark River and Taylor Sloughs water levels are about 0.25m and about 0.31m, respectively.  Paleo-based salinity values in Florida Bay are about 10 salinity units less than observed values in nearshore areas and about 5 salinity units less in outer regions.  The freshwater flow currently discharged from the managed hydrologic system into tidal waters was found to be sufficient to make-up the estimated freshwater deficit.  This newly synthesized picture of pre-drainage hydrology is being implemented in PMs for CERP alternative evaluations and monitoring data assessments.  Future activities include a similar effort on the southwest Florida Gulf coast.  Restoring the natural hydrology and salinity is thought to be the best management practice to allow the unique Everglades ecosystem to adapt to changes in climate, hydrology, and sea level.



Frank Marshall,
Oct 14, 2011, 9:43 AM