Project: Hydrologic Variation and Ecological Processes in the Mangrove Forests of South Florida: Response to Restoration

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Location: Southwest Coast; Miami-Dade, Monroe and Collier Counties

Principal Investigators: James E. Saiers, j.saiers@yale.edu, 203.432.5155; Thomas J. Smith III, Tom_J_Smith@usgs.gov, 305.348.1267

Project Personnel: Carl Bolster, c.bolster@yale.edu, Gordon Anderson, Gordon_Anderson@usgs.gov

Other Supporting Organizations: Yale University School for the Environment, National Park Service

Associated Projects: Vegetation Dynamics in the Land-Margin Ecosystems: The mangroves of south Florida (Thomas J. Smith III); Understanding and Predicting Global Climate Change Impacts on the Vegetation and Fauna of Mangrove Forested Ecosystems in Florida (Thomas J. Smith III & Carole C. McIvor)

Overview & Status: This project focuses on the hydrology of the mangrove-marsh ecotone of Everglades National Park and on the linkages between hydrologic characteristics and mangrove ecosystem function. The objectives of this research are to (1) quantify groundwater and surface-water flow dynamics within the coastal mangrove zone and within the adjacent freshwater marsh, (2) define the response of fluid flow characteristics to changes in weather and water management practices, and (3) derive relationships between hydrologic conditions and vegetation indices of the mangrove-marsh ecotone. A two-dimensional finite-difference model was constructed that accurately predicts the temporal variability in water levels across a 20-mile long region, situated in the central portion of Shark River Slough. The domain of this fine-resolution model is currently being extended to include the coastal mangrove zone, and we are modifying the model formulation to account for complications associated with the mixing of fresh and saline waters.

Needs & Products: The results of this research will contribute to fulfilling a suite of critical information needs, as outlined in the 1996 science sub-group report on south Florida ecosystem restoration. Six critical science needs are addressed directly by this study of the mangrove zone and upgradient freshwater marsh, (The relevant pages of the sub-group report, where the science needs are described, are given in parentheses): 1) Quantitative information on hydroperiods and hydropatterns are needed to drive ecological models of wetlands (pg 82); 2) Hydrologic models are needed to identify how changes in structure and management influence the volume, timing, and distribution of flows in Everglades National Park (pg 83); 3) Models that include both surface-water and groundwater components must be developed and should extend from the freshwater marsh to the coast (pg 87); 4) Physical models of the mangrove zone must be constructed to provide water depths and salinities as functions of freshwater inflow from upstream and tidal forces (pg 90); 5) Information on the relationship between freshwater discharge from Shark Slough and salinity dynamics in Florida Bay is required (pg 91); 6) Hydrodynamic models for Florida Bay rely on accurate estimates of groundwater and surface water inflow (pg 93). A manuscript entitled "Development and Evaluation of a Mathematical Model for Surface-Water Flow within the Shark River Slough of the Florida Everglades" has been submitted to the journal Water Resources Research.

Application to Everglades Restoration: Results of this work will provide new information and tools critical in guiding Everglades restoration, including estimates of freshwater flows into estuaries within the Park and a tested means to forecast how these freshwater discharges are affected by changes in system structure and operational procedures.