Abstract
Coastal groundwater flow investigations at the Cutler site of the Biscayne Bay south of Miami, Florida, gave rise to the dominating concept of density-driven flow of seawater into coastal aquifers indicated as a saltwater wedge. Within that wedge, convection-type return flow of seawater and a dispersion zone were concluded to be the cause of the Biscayne aquifer ‘seawater wedge.’ This conclusion was merely based on the chloride distribution within the aquifer and on an analytical model concept assuming convection flow within a confined aquifer without taking non-chemical field data into consideration. This concept was later labeled the ‘Henry problem,’ which any numerical variable-density flow program has to be able to simulate to be considered acceptable. Revisiting the summarizing publication with its record of piezometric field data (heads) showed that the so-called seawater wedge was actually caused by discharging deep saline groundwater driven by regional gravitational groundwater flow systems. Density-driven flow of seawater into the aquifer was not found reflected in the head measurements for low and high tide which had been taken contemporaneously with the chloride measurements. These head measurements had not been included in the assumption of a seawater wedge and associated dispersion zone and convection cell. The Biscayne situation emphasizes the need for any chemical interpretation of flow pattern to be backed up by head data as energy indicators of flow fields. At the Biscayne site density-driven flow of seawater did not and does not exist. This conclusion was confirmed by five independent methods. The hydrostatic use of vertical buoyancy forces needs, under hydrodynamic boundary conditions, to be replaced with buoyancy forces along the direction of the pressure potential forces [(grad p)/density] which, in the subsurface, can be pointed in any direction in space.
Highlights
In the 1950s and 1960s, the USGS investigated the role of seawater in the flow pattern of the Biscayne aquifer near Miami, Florida (Fig. 1), by measuring heads and chemistry in piezometer nests
The objective of this paper is to report the results of this review after first outlining the physical differences between ‘density-driven flow’ and gravitationally driven ‘groundwater flow systems.’
In an attempt to explain the pattern of equal isochlor lines at a test site for saltwater intrusion at Biscayne Bay near Miami (Cooper et al 1964), groundwater flow pattern was derived from chemical data and an analytical model calculation and taken as proof for the invasion of seawater into the Biscayne aquifer
Summary
In the 1950s and 1960s, the USGS investigated the role of seawater in the flow pattern of the Biscayne aquifer near Miami, Florida (Fig. 1), by measuring heads and chemistry in piezometer nests. Most of the essential data were collected, and their interpretations were published by Cooper et al (1964). These authors had published individual papers previously dealing with their part of these investigations as Cooper (1959), Glover (1959), Henry (1959, 1960a, b, 1962, 1964) and Kohout (1960a, b). A selection of text books and handbooks spreading this concept includes Bear (2007a, Fig. 9–37, 2007b, Fig. 12.4), De Wiest All these books refer to the field work and the related data interpretation summarized by Cooper et al (1964). The concepts contained in Cooper et al (1964) have been widely adopted as a base for
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
