Hypothesis 1: Variable inflows from upstream sources, SLR, and storm surge interact to alter surface water residence time, salinity, and groundwater intrusion in the oligohaline ecotone.
Approach - This hypothesis will be addressed using a combination of field measurements, hydrologic modeling, and satellite observations. We will maintain continuous measurements of groundwater and surface water levels, temperature, salinity, and chemistry in the oligohaline ecotone of both sloughs. Rainfall and ET from meteorological stations will be combined with surface water inflows, outflows, and water levels measured across ENP into a water balance. Water balance parameters and residence times (the quotient of inputs to volume of surface water) will be compared before, during, and after construction of the Tamiami bridge. Field data will be input to two hydrodynamic models. Expanding upon prior modeling efforts, the variable-density groundwater flow model SUTRA-MS will not only be used to quantify groundwater discharge but also coupled with P concentrations in the shallow groundwater to provide a better understanding of the roles that groundwater discharge plays in the water and nutrient budgets. We will develop a reach-scale particle-tracking model to track the fate and transport pathways of water and dissolved constituents (i.e., DOC, nutrients) from the slough to the integrated mangrove-surface water-groundwater system and back to the slough over tidal and seasonal cycles, with water and chemical residence times being expressed in terms of probability density functions. Wetland Interferometric Synthetic Aperture Radar will be used to provide high spatial-resolution (1-5 m pixels) water level change maps over a greater region of the oligohaline ecotone of SRS by comparing pixel-by-pixel observations over time. Water level changes in the mangrove marshes will be used to constrain the particle-tracking model. Findings will be compared to other coastal ecosystems in the Caribbean, particularly through ongoing FCE hydrological and ecological investigations in coastal mangrove communities in Celestun and Sian Ka''an, of the Yucatan Peninsula, Mexico, which are geologically and ecologically similar to FCE and at risk of future urban development and SLR.
Hypothesis 2: Stakeholder uncertainties over SLR will increase conflicts over Everglades restoration implementation and will affect freshwater delivery to the oligohaline ecotone.
Approach - We will examine the production of uncertainties and conflict by focusing our research on two key sites where these processes are particularly visible: Stormwater Treatment Area 5 (STA5) and the S-12 structures (along the Tamiami Trail that control the flow of water into northwestern SRS). Located within the Everglades Agricultural Area (EAA), STA 5 is a constructed wetland designed to improve input water quality to the Everglades by removing P. The establishment of nesting snail kites (an endangered species) has affected STA 5 operations. New uses of STA 5 and surrounding areas ? e.g., for birding, duck hunting, cultural heritage claims ? reveal the social complexity of water management infrastructure. We need to understand how the conflicts in this region may be overcome, in order to release more water through the Tamiami Trail (currently a barrier to sheet flow), and ultimately to the oligohaline ecotone. Operations of the S-12 structures, and plans for water flow under the newly constructed bridge, are governed by a complex array of federal and state regulatory agencies, which often must balance competing water delivery and flood control needs with endangered species impacts. In addition, water quality concerns have further hampered S-12 operations and restoration planning. Using a multi-methodological approach, we will interview local residents, recreationalists, and resource managers, as well as analyze archival data and restoration planning documents to understand the management (institutional) and local perspectives that create connections and disconnections of water in STA 5 and the S-12 structures and eventually to the oligohaline ecotone. We will also determine from water managers and engineers responsible for site design whether climate change has been considered in the design and operations of both of these sites in order to understand long-term influences on the oligohaline ecotone.