REPORT OF INVESTIGATIONS NO. 42


1 to 3 days. The data were used to determine the quality of water
prevalent in the area at a given time and to help determine the
interrelations between surface water and ground water.
 Ground-water characteristics were determined by collecting
data concerning water levels, surface and subsurface geology, and
water chemistry from an inventory of existing wells in the Green
Swamp area and vicinity (fig. 2). Information on the depth of the
well, the amount of casing, and the depth to static water level was
recorded for more than 600 wells. Most of the inventoried wells
penetrated the Floridan aquifer. The approximate elevation of land
surface above mean sea level was determined at each well by use
of either altimeter, topographic maps, or spirit level. These data
were supplemented by selected data collected prior to this
investigation and by test drilling to provide better coverage of
the area.
 The well-numbering system that is derived from latitude and
longitude coordinates is based on a state-wide grid of 1-minute
parallels of latitude and 1-minute meridians of longitude, shown in
figure 3.
 Instruments were used to record continuously the water-level
fluctuations in the various aquifers. These data were supplemented
by periodic determinations of water levels and chemical character-
istics of water in selected wells in order to evaluate areas of
recharge and discharge for the aquifers.
 The wells in which continuous and selected periodic water-level
data, and quality-of-water data were collected, are presented in
table 2.
 During the periods October to December 1959 and May to June
 1962, water-level measurements were made to prepare piezometric
 maps which show the direction of water movement in the Floridan
 aquifer. Hydraulic gradients scaled from these maps were used to
 infer rates of water movement.
 To obtain general information on the occurrence of artesian
 and nonartesian ground water in the Green Swamp area, 26 test
 wells were drilled at 16 different sites. At 9 of these sites a pair
 of wells were drilled (one into the Floridan aquifer and one into
 the nonartesian aquifer). A summary of test-well data is presented
 in table 3. During the drilling, samples of rock cuttings were
 collected. The lithology of the various formations and significant
 changes in water levels were recordered in the well log.
 Examination of rock cuttings of selected wells were supplemented