Study Sites
Four of the subdivisions are located in Eau Claire County and two in
LaCrosse County in west-central Wisconsin (Figure 1 and Table 1). The
subdivisions are situated on sand and loamy sand soil on glacial outwash or
river terrace deposits. The soil slope is 0 to 6 percent in Oak Park and Pine
Grove-Deer Park subdivisions and 0 to 2 percent in the other subdivisions.
The mean depth to the water table, the mean depth of the water-supply wells,
and the mean depth of the well casings for each subdivision are presented in
Table 1.
All wells in Sandy Knolls, Oak Park, Briarwood and Lowes Creek
subdivisions terminate in a water-table aquifer composed of sandy sediment.
One exception is a well in Lowes Creek subdivision which terminates in
sandstone under the sandy sediment.   In Pine Grove-Deer Park subdivision, 21
wells terminate in the upper sandy sediment, 17 wells in sandstone under the
sandy sediment, and one well in granite under the sandy sediment. The initial
construction date, total area, number of septic systems, mean lot size, mean
number of people per home, and mean number of bedrooms per home for each
subdivision are presented in Table 2. The hydraulic gradient, hydraulic
conductivity, average linear velocity of ground water, ground-water flow
length across the subdivision, and travel time of ground water beneath each
subdivision are presented in Table 3. The hydraulic gradients were determined
from water-table maps constructed from data obtained from well construction
reports of water-supply wells and elevations of permanent rivers. Hydraulic
conductivity values were determined from specific capacity data obtained from
well construction reports using the method described by Bradbury and
Rothschild (1985).  The average linear velocity of the ground water was
S   calculated using Darcy's Law with porosity equal to 0.25.   The distance across
the subdivisions was obtained from aerial photographs, 7-1/2 minute

topographic maps, or plat maps.