Measurement of hydrodynamics and pore water chemistry in intertidal groundwater systems.

Gibbes, B., Robinson, C., Li, L., and Lockington, D., 2007. Measurement of hydrodynamics and pore water chemistry in intertidal groundwater systems, SI 50 (Proceedings of the 9th International Coastal Symposium), 884 – 894. Gold Coast, Australia, ISSN 0749.0208 Oceanic forcing due to tides and waves results in complex and dynamic pore water flows in intertidal groundwater systems. In the presence of fresh groundwater discharge these flows are further complicated by variable density effects. The recirculation of seawater through these systems significantly influences the fate and fluxes of subsurface terrestrial contaminants discharging to coastal waters. As a result, understanding the dynamics and variability of the flow, transport and reaction processes in intertidal groundwater systems is crucial for accurate predictions of chemical loading to the receiving coastal ecosystem. Measurements of pore water flows and chemistry in the intertidal region are difficult due to the various forces acting on the system, each of which operate over a wide range of spatial and temporal scales. In this paper we provide a review of monitoring techniques that are applicable to sandy intertidal groundwater systems. In particular we focus on relatively inexpensive equipment, based on commercially available pressure transducers and water quality probes, which have been successfully employed to collect simultaneous hydrodynamic and chemical data. Results from two recent field investigations are presented to illustrate the range of measurements which can be obtained. [ABSTRACT FROM AUTHOR]