Advection Within Shallow Pore Waters of a Coastal Lagoon, Florida

Autor: Jaye E. Cable, Jonathan B. Martin, Joel S. Steward, Mary K. Lindenberg, Peter W. Swarzenski
Rok vydání: 2004
Předmět:
Zdroj: Ground Water. 42:1011-1020
ISSN: 1745-6584
0017-467X
DOI: 10.1111/j.1745-6584.2004.tb02640.x
Popis: Ground water sources can be a significant portion of a local water budget in estuarine environments, particularly in areas with high recharge rates, transmissive aquifers, and permeable marine sediments. However, field measurements of ground water discharge are often incongruent with ground water flow modeling results, leaving many scientists unsure which estimates are accurate. In this study, we find that both measurements and model results are reasonable. The difference between estimates apparently results from the sources of water being measured and not the techniques themselves. In two locations in the Indian River Lagoon estuarine system, we found seepage meter rates similar to rates calculated from the geochemical tracers 222 Rn and 226 Ra. Ground water discharge rates ranged from 4 to 9 cm/d using seepage meters and 3 to 20 cm/d using 222 Rn and 226 Ra. In contrast, in comparisons to other studies where finite element ground water flow modeling was used, much lower ground water discharge rates of ~0.05 to 0.15 cm/d were estimated. These low rates probably represent discharge of meteoric ground water from landrecharged aquifers, while the much higher rates measured with seepage meters, 222 Rn, and 226 Ra likely include an additional source of surface waters that regularly flush shallow (< 1 m depth) sediments. This resultant total flow of mixed land-recharged water and recirculated surface waters contributes to the total biogeochemical loading in this shallow estuarine environment.
Databáze: OpenAIRE
Externí odkaz: