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An autonomous, electromagnetic seepage meter to study coastal groundwater/surface-water exchange

Open-File Report 2004-1369
By: , , and 
https://doi.org/10.3133/ofr20041369

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Abstract

The bi-directional exchange of groundwater with coastal surface waters may influence not only coastal-water and geochemical budgets, but may also impact and direct coastal ecosystem change. For example, the widespread discharge of nutrient-enriched submarine groundwater into an estuary or lagoon may contribute directly to the onset and duration of eutrophication, as well as the development of harmful algal/bacterial blooms. Most often, this submarine groundwater discharge (SGD) (defined here as a composite of meteoric, connate and sea water) occurs as hard-to-constrain diffuse seepage, rather than as focused discharge either through vent or collapse features. As a result, quantifying SGD rates has remained difficult for both oceanographers and hydrologists alike. This report describes an adaptation of an old tool, the Lee-type manual seepage meter, with a state-of-the-art electromagnetic flow meter that enables rapid, autonomous, bi-directional measurements of fluid exchange rates across the sediment/water interface. When such measurements are coupled and interpreted with surface and groundwater pressure, salinity and temperature data, as well as other complementary measurements such as excess watercolumn 222Rn activities, then realistic groundwater/surface-water exchange rates can be obtained in dynamic coastal environments.

Suggested Citation

Swarzenski, P.W., Charette, M., and Langevin, C., 2004, An autonomous, electromagnetic seepage meter to study coastal groundwater/surface-water exchange; 2004; OFR; 2004-1369;

ISSN: 2331-1258 (online)

Table of Contents

  • Introduction
  • Principles of an EM Seepage Meter
  • Field Testing the EM Seepage Meters
  • Acknowledgments
  • References
Publication type Report
Publication Subtype USGS Numbered Series
Title An autonomous, electromagnetic seepage meter to study coastal groundwater/surface-water exchange
Series title Open-File Report
Series number 2004-1369
DOI 10.3133/ofr20041369
Year Published 2004
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description 4 p.
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