Project Summary Sheet

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

Web Sites: http://sis2.cr.usgs.gov Science Information System (SIS) # 5004448

Location (Subregions & Counties): Southeast coast, Southwest coast; Miami-Dade, Monroe, Collier

Funding (Source): Critical Ecosystems Studies Initiative (CESI) from Everglades National Park

Principal Investigator(s): Thomas J. Smith III, Tom_J_Smith@usgs.gov; 727-803-8747 x 3130; James E. Saiers, j.saiers@yale.edu, 203-432-5155

Project Personnel: Gordon Anderson, Gordon_Anderson@usgs.gov; Christa Walker, christa_walker@usgs.gov

Supporting Organizations: National Parks Service (NPS)

Associated / Linked Projects: Vegetation Dynamics in the Land-Margin Ecosystems — The mangroves of south Florida (Smith); Understanding and Predicting Global Climate Change Impacts on the Vegetation and Fauna of Mangrove Forested Wetlands in Florida (Smith/McIvor); TIME — Tides and Inflows to the Mangroves of the Everglades (Schaffranek/Jenter). Landscape models for the mangrove forests of the Everglades (Twilley/Doyle).

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 ground water 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-kilometer 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: Results from this research 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 (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 ground water 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 ground water and surface water inflow (pg 93). Two refereed journal manuscripts have been published. One entitled "Development and Evaluation of a Mathematical Model for Surface-Water Flow within the Shark River Slough of the Florida Everglades" has been published in the Journal of Hydrology (2002, Vol. 259, pgs. 221-235). The second paper, entitled "Determination of Specific Yield for the Biscayne Aquifer with a Canal-Drawdown Test" was published in Ground Water (2001, Vol. 39, No. 5, pgs. 768-777).

 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. The models will be related to performance measures currently being developed for the mangrove transition zone.