Environmental Engineering Reference
In-Depth Information
Recent flowmeter logging in the Biscayne aquifer ( Cunningham and Sukop,
2011 ) indicates that these stratiform, touching-vug, macroporous, bioturbated
zones can stack to form an extremely transmissive aquifer over a wide-ranging
area, with macroporous Ophiomorpha -dominated zones extending over a lateral
distance of at least 8.4 km ( Fig. 2 ). Macroporous zones with maximum
Ophiomorpha ichnofabrics are even more widely distributed at the hundred-
kilometer scale in the “bryozoan facies” of the Miami Limestone assigned to
MIS 5e by Multer et al. (2002) and mapped by Hoffmeister et al. (1967) in south-
ern Florida. But even these distances are conservative in comparison to the broad
extent of modern, shallow-subtidal, carbonate-sand environments intensively
burrowed by endobenthic callianassids ( Curran and Martin, 2003; Shinn, 1968 ).
The range in intrinsic permeability values calculated from LBM for five
Biscayne aquifer subsamples with macropore networks dominated by an Ophio-
morpha ichnofabric is between 15
10 6 darcies ( Cunningham and
Sukop, 2011; Cunningham et al., 2009 ; Fig. 5 and Table 1 ). Intrinsic permeabil-
ity is a fluid-free conductance parameter that depends only on the properties of a
solid matrix, not on the properties of a fluid passing through it. The conductance
parameter, hydraulic conductivity, which is commonly used by hydrologists, is
related to both the properties of the matrix and the fluids moving through
it ( Freeze and Cherry, 1979 ). The important point is that the five intrinsic per-
meability values derived from LBM-calculated values ( Cunningham and
Sukop, 2011, Cunningham et al., 2009 ) are very high ( Fig. 5 and Table 1 ).
10 3 and 27
FIGURE 5 Lattice Boltzmann-calculated intrinsic permeability and laboratory air-permeability
values derived from carbonate samples with networks of ichnofabric-related macroporosity (modi-
fied from Cunningham and Sukop, 2011 ).
Search WWH ::




Custom Search