Author(s): Evgeny A. Kontar; William C. Burnett
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Abstract: Submarine springs and seeps are an overlooked source of fresh water and dissolved species to the ocean. Volumetric estimates of their global extent range over several orders of magnitude. This is unfortunate as groundwater discharge into the ocean should occur anywhere that an aquifer with a positive head is hydraulically connected to the sea, i. e., most coastal areas. Submarine groundwater discharge has been documented to be significant for nutrient input in some regions, and could be of importance for issues relating to pathways of pollutants to the ocean as well as various naval operations (acoustic interference, etc. ). The problem is how to find and measure direct groundwater flow into the coastal zone. Prior studies indicate that groundwater seepage is usually patchy, diffuse, and temporally variable. In addition, we have shown that radon (222 Rn) can be a valuable tracer of direct groundwater discharge (Burnett et al., 1996). Also changes in the radon emission of groundwater have come to be known as one of the precursory phenomena of an earthquake (Noguchi & Wakita, 1977; Mogi, 1995; Igarashi & Wakita, 1995). Finding points of discharge is an important first step, especially when contaminated groundwater may be involved. A modeling approach may also be used to estimate quantitatively the volumes of groundwater being discharged.
Year: 1999