REPORT OF INVESTIGATIONS NO. 42


 The principal importance of an aquifer is its ability to transmit
and store water. The coefficients of permeability (P) and
transmissibility (T) are measures of the capacity of an aquifer to
transmit water. Permeability is usually determined by laboratory
measurements of a minute part of the aquifer, whereas transmissi-
bility usually determined in the field by aquifer tests, represents
the average permeability for a localized area of the aquifer.
 The coefficient of storage (S) is a measure of the capacity of
an aquifer to store water. The coefficient of storage for artesian
aquifers is usually determined by pumping tests and may range
from about 0.00001 to 0.001. The coefficient of storage for
nonartesian aquifers can be determined by pumping tests or
laboratory methods and may range from about 0.05 to 0.30 and, for
all practical purposes, equals the specific yield.
 Coefficients of permeability were determined by laboratory
analysis for samples from the nonartesian and artesian (Floridan)
aquifers in the Green Swamp area (see tables 8 and 9). Aquifer
tests were made at selected sites and the data were analyzed to
determine coefficients of transmissibility using (1) the type curve



TABLE 8. Hydrologic analyses of disturbed sand samples from a test hole in
 Lake Parker near Lakeland

 (Analyses by U. S. Geological Survey Hydrologic Laboratory, Denver,
 Colorado.)

 Depth below Specific Coefficient
 Sample lake bottom Porosity yield of permeability
 number (feet) (percent) (percent) (gpd/ft2)

 1 6-7 37.1 36.3 75
 2 11-12 34.0 33.4 40
 3 15-16 35.0 34.6 50
 4 20-23 32.7 32.1 80
 5 24-26 34.2 34.0 20
 6 27-28 35.2 38.4 60
 7 35-37 36.9 35.8 90
 8 44-45 36.2 34.5 150
 9 50 32.2 31.0 95
 10 55-56 39.7 37.3 180
 11 60 44.8 43.9 110
 12 70 45.4 41.7 115
 13 73-77 43.2 39.0 40