Abstract Introduction Study Area Aquifer Framework and Definitions Transmissivity, Hydraulic Conductivity and Storage Coefficient >Hydrogeology > Sediment Hydraulic Conductivity   -  W. Broward Co.   -  Central and E. Broward Co. - Aquifer Delineation - Transmissivity Distribution Ground-Water Flow System Summary References Cited PDF Version

The hydraulic conductivity framework (permeability distribution) of the surficial aquifer system is portrayed by superimposing ranges of hydraulic conductivities on the eight geologic sections prepared by Causarás (1985). The framework is shown in figures 15 to 22 (location of well and sections are shown in fig. 3). Some aspects of areal variations in the lithology of geologic formations are included here as part of the discussion of the hydraulic conductivity framework because of relations between lithology and hydraulic conductivity. Detailed lithologic logs for each well and a description of the geology of the aquifer system are contained in the report by Causarás (1985). In addition to the hydraulic data and municipal well data reported in the previous section, other information used to construct the hydraulic conductivity framework included:

• Flow rates obtained while drilling the test holes by the dual-tube reverse-air method;
• Hydrologic inferences from inspection of all the geologic samples;
• Published values of hydraulic conductivity in relation to grain size and sorting for clastic sediments and sandstone; and
• Grain-size and sorting descriptions by Causarás (1985) and sieve analysis of selected samples.

The range of hydraulic conductivities of the materials that make up the surficial aquifer system is about seven orders of magnitude–from more than 10,000 ft/d for the more permeable cavernous zones to about 0.001 ft/d or less for dense green clay. For the hydraulic conductivity sections, this range is divided into five categories, and general lithologies are shown in table 7. Virtually all materials having hydraulic conductivities more than 1,000 ft/d occur only in the Biscayne aquifer–the possible exception being local areas of the gray limestone aquifer. Large supply wells are usually finished in materials that have high to very high permeabilities. Materials that have moderate permeability are considered the lower limit useful in this area as an aquifer for water supply, primarily for domestic purposes. Materials of low permeability (from 0.1 to 10 ft/d) are not generally used for supply but permit seepage or leakage of water to more permeable beds. Materials of very low permeability to practically impermeable (less than 0.1 ft/d) will retard ground-water circulation considerably where present in thicknesses of a few feet or more.

The sections (figs. 15-22) provide an indication of the horizontal hydraulic conductivity of the rocks or sediments. Because of the scale of the sections, rapid vertical changes in lithology and permeability could not be shown. Where it appears that a few or several thin zones of high permeability occur, separated by less-permeable materials (for example, dense limestone), the higher range is shown. In such instances, the sections give a more accurate portrayal of the capability of the formation to permit lateral movement of water than to permit vertical movement.

Figure 15. (left) Hydrogeologic section A-A' showing ranges of hydraulic conductivity. [larger image]	Figure 16. (right) Hydrogeologic section B-B' showing ranges of hydraulic conductivity. [larger image]

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Figure 17. (left) Hydrogeologic section C-C' showing ranges of hydraulic conductivity. [larger image]	Figure 18. (right) Hydrogeologic section D-D' showing ranges of hydraulic conductivity. [larger image]

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Figure 19. (left) Hydrogeologic section E-E' showing ranges of hydraulic conductivity. [larger image]	Figure 20. (right) Hydrogeologic section F-F' showing ranges of hydraulic conductivity. [larger image]

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Figure 21. (left) Hydrogeologic section G-G' showing ranges of hydraulic conductivity. [larger image]	Figure 22. (right) Hydrogeologic section H-H' showing ranges of hydraulic conductivity. [larger image]

Download the PDF version of the report plates (Figures 15-22, 40 & 41, 23.3 MB).

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Table 7. Approximate ranges of hydraulic conductivity of materials that compose the surficial aquifer system, Broward County. [Range, in feet per day; >, greater than; <, less than. Geologic formation: Qa, Anastasia Formation; Qf, Fort Thompson Formation; Qk, Key Largo Limestone; Qm, Miami Oolite; Qp, Pamlico Sand; Th, Hawthorn Formation; Tt, Tamiami Formation; Tth, undifferentiated Tamiami Formation or Hawthorn Formation; Ttl, Tamiami Formation, lower part; Ttu, Tamiami Formation, upper part.]
Horizontal hydraulic conductivity		Materials - lithology and porosity	Geologic formations
Qualitative permeability	Range
Very high	>1,000	Solution-riddled limestone, commonly shelly or sandy.	Qf, Qa
		Calcareous sandstone, may be shelly or have shell fragments; solution holes or rib-like channels.	Qa, Tt
		Coralline limestone, reefal, very porous.	Qk
High	100-1,000	Gray, shelly limestone, locally sandy, relatively soft.	Tt
		Limestone or calcareous sandstone interbedded with sand, or with sand partially filling cavities.	Qa, Tt, Qf
		Coarse shell sand and quartz sand.	Tt
		Dense, charcoal gray to tan limestone with some solution channels, usually shelly or sandy.	Ttu
Moderate	10-100	Very fine to medium, relatively clean quartz sand.	Qp, Qa, Tt
		Fine to medium quartz and carbonate sand.	Tt
		Cream-colored limestone with minor channels.	Qf, Qa
		Tan, cream, or greenish limestone, locally containing shell sand.	Tt
		Calcareous sandstone and sand.	Tt, Qa
		Slightly clayey or sandy, gray limestone	Tt
		Oolitic limestone.	Qm
Low	0.1-10	Very fine to medium sand with some clay, silt, or lime mud, locally shelly.	Tt, Qf, Qa
		Soft gray or buff limestone with silt and fine sand.	Tt
		Dense, calcareous sandstone.	Tt
		Light-green, fine-grained foraminiferal limestone with very fine quartz sand.	Tt
		Dense, hard limestone with very small cavities or channels; approximately equal mixtures of sand, shell fragments, and lime mud.	Qf
Very low to practically impermeable.	<.01	Green clay or silt; locally with very fine sand.	Th, Tth, Ttl, Ttu,
		Sandy, shelly lime mud.	Tt
		Very dense, hard limestone with no apparent solution cavities or fractures.	Qf