Seawater intrudes into the coastal surficial aquifer system beneath ENP and mixing with the fresh groundwater to produce a brackish groundwater mixing zone. This brackish groundwater contains elevated concentrations of phosphorus due to geochemical reactions such as ion exchange and carbonate mineral dissolution. The brackish groundwater discharges to the surface water of the Everglades.
Source: René Price
This theme addresses Everglades hydrology from a variety of disciplinary perspectives to advance an integrated understanding of the processes that shape the Everglades as a eco-socio-hydrological system. For at least the past century, water management decisions, rather than natural processes, have controlled the distribution of sheet flow from Lake Okeechobee to the southern Everglades. Our research indicates that over the last several decades (10-40 yr) groundwater salinity and surface water levels in the oligohaline ecotone were most strongly influenced by SLR, as inputs of upstream freshwater were insufficient to counteract the marine transgression. As a result, we need to understand how water/restoration management practices and perceptions interact with longer-term trends in climate variability and SLR to produce the contemporary Everglades. Hydrologists, anthropologists, geographers and modelers will work together to explore future paths for water management decisions and estimate their impact on surface and groundwater availability and quality in the oligohaline ecotone, and to evolving land-water system dynamics. We expect that climate processes of rainfall and evapotranspiration (ET) along with SLR will continue to be the dominant drivers of water availability across the Everglades landscape, but that the balance between regional water demand and restoration efforts will fine tune the position of the oligohaline ecotone, and its surface and groundwater quality. Water demand by urban and agricultural users competes with the need for additional water to sustain ecosystems (and the services they provide) in ENP (Kirsch 2005; Ogden 2008). The extremely flat landscape and porous nature of the underlying limestone aquifer as well as fragmentation of this once interconnected watershed by levees, roads, and canals makes deliveries of additional water to ENP an engineering challenge. Future water demands by urban and agricultural users, concerns of flooding with SLR, and future economic and climate-related uncertainties are all concerns for water managers and a source of friction shaping hydrologic conditions in the oligohaline ecotone. We will examine the social, institutional, and economic processes that have produced current hydrologic disconnections within the broader watershed and its ultimate impact on the oligohaline ecotone. This research will provide guidance regarding the management of emergent ecosystems, using approaches from science and technology studies that examine the ways social actors and communities approach risk and scientific uncertainty.