See more from this Division: Topical Sessions
See more from this Session: Advances in Surface Water–Groundwater Interactions: Investigations of Rivers, Lakes, and Wetlands
Abstract:
The SGD due to each of these mechanisms has been quantified in an estuary on Cape Cod, MA using direct measurements and modeling. The spatial location of discharge due to each mechanism was estimated, and temporal variability investigated. Because the origin and flowpaths of waters driven by each mechanism is different, it is expected that each would contribute solutes in different concentrations. This is illustrated in Waquoit Bay with measurements of radium isotopes in porewater and direct groundwater discharge. Combination of fluid flux and measured radium activities indicates that 80% of the total 226Ra flux occurs in the zone of discharge driven by interface density gradients, which supplies an estimated 40% of fluid discharge. Similar disproportion between fluid and solute fluxes occurs in other discharge zones, indicating that physical forcing mechanisms and resulting flowpaths may have a strong control on chemical loading. This has implications for use of geochemical tracers in estimating SGD, and indicates that an understanding of both the driving mechanisms and associated solute concentrations is essential for accurate estimation of groundwater-derived chemical fluxes to coastal waters.
See more from this Division: Topical Sessions
See more from this Session: Advances in Surface Water–Groundwater Interactions: Investigations of Rivers, Lakes, and Wetlands