FLORIDA GEOLOGICAL SURVEY


 Another option is to consider the IAS as a complex system of nearly statewide extent, recognizing that
aquifers within this predominantly confining/semi-confining system are sub-regional to regional, yet the
overall correlative hydrostratigraphic package is unique relative to the surficial and Floridan aquifer
systems. Along this line of reasoning, one may consider the confining/semi-confining sediments in the
northern part of the study area as a low-permeability hydrogeologic facies of the IAS. It is noteworthy
that hydraulic characteristics of semi-confining zones identified in Florida are considered "aquifers" or
"permeable zones" in other parts of the country, thus lending support to the statewide IAS concept. Fetter
(2001) describes an aquifer as a "geologic unit that can store and transmit water at rates fast enough to
supply reasonable amounts to wells. The intrinsic permeability of aquifers would range from about 10-2
darcy upward." Albeit subjective, clayey sands often considered part of semi-confining (and
"confining?") units in Florida fall within Fetter's (2001) aquifer definition.

 The proposal of a statewide IAS, however, may lead to perception issues for the lay public as well as
concerns regarding aquifer-system definitions. Many geoscientists contend that statewide use of the IAS
name is inconsistent with existing aquifer-system definitions. Moreover, use of the IAS name in the
northern study area may incorrectly imply to the non-scientist that significant water-yielding
"intermediate" strata exist in the region, which is not the case.