Stalker, J. C., Florida International Unversit, Miami, USA, jstalker@fiu.edu
Price, R. M., Florida International University, Miami, USA, pricer@fiu.edu
Swart, P. K., Rosenstiel School of Marine and Atmospheric Chemistry, University of Miami, Miami, USA, pswart@rsmas.miami.edu

SPATIAL AND TEMPORAL INPUTS OF FRESHWATER AND SUBMARINE GROUNDWATER DISCHARGE TO A SUBTROPICAL ESTUARY USING GEOCHEMICAL TRACERS, BISCAYNE BAY, SOUTH FLORIDA

Biscayne Bay is a coastal estuary in Southeast Florida that historically has received significant quantities of fresh submarine groundwater discharge. Water management practices in the region have reduced these inputs. In an effort to differentiate the freshwater inputs to the bay, samples of precipitation, canal water, groundwater, and bay surface water were collected from July 2004 to July 2006 and analyzed for salinity, stable isotopes of O, and H and Sr2+/Ca2+ ratios. These tracers were used in three mixing models and then combined to trace the magnitude and timing of the fresh water inputs to the estuary. The modeling results indicate rainfall dominating freshwater inputs in the wet season with the ratio of canal-precipitation-groundwater inputs of 30%-60%-10%, respectively. In the dry season canal inputs almost equal precipitation with the ratio of canal-precipitation-groundwater inputs changing to 40%-45%-15%, respectively. For a bay wide water budget that includes saltwater and freshwater mixing, fresh groundwater accounts for 2% of the total input. However, most groundwater inputs occur along the western shoreline of the bay, while precipitation dominates in the eastern portion of the bay.

Oral presentation

Presentation is given by student: No
Session #:089
Date: 03-03-2008
Time: 16:30