The Recharge Area and Water Quality of the Stevens Point Municipal Well Field

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Date
1987-05Author
Renaud, Richard K.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
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Show full item recordAbstract
Determining the area from which the City of Stevens Point Municipal
Supply Wells draws recharge waters is important first step in
protecting the city's water supply. In determining the recharge area,
land uses that may affect the water quality of the aquifer may be
discouraged. To determine the groundwater flow characteristics of the
recharge area 9 piezometers and 12 water table observation wells were
used to estimate to groundwater flow approaching the well field.
Nested well systems were installed both east and west of the Plover
River to determine the extent of the cone of depression and whether the
cone extended to or beyond the Plover River. Water table observations
revealed that the cone of depression extends beyond the Plover River
during most of the year, indicating that water from the river and east
of the river is drawn into the aquifer near the well field.
Piezometers placed in the bed of the river verified that the river was
recharging the aquifer near the well field. Observations from the
nested well systems demonstrated that the groundwater flow approaching
the city supply wells is predominately horizontal, suggesting that the
groundwater flow is dominated by the pumpage from the city supply
wells. The horizontal gradients east of the Plover River indicated
that pumpage from the city wells was affecting groundwater flow east of
the river, creating the potential for groundwater flow beneath the
river bed. The aquifer water quality was examined through sampling all
piezometers, monitoring wells, city supply wells, regional private
water supply wells, and regional surface water bodies. All samples were
analyzed for inorganic constituents to examine the aquifer water
quality of the well field region and to use the specific constituents
as natural traces of groundwater flow. The sampling revealed isolated
high concentrations of many constituents. An area of impacted water
was detected in the deeper aquifer adjacent to the well field east of
the river. The elevated concentrations of nitrates, sulfates and
chlorides suggested that the impacts were associated with agricultural
fertilizers, animal wastes and septic systems. Impacted groundwater
was also detected along Highway 66. Elevated concentrations of
ammonia, sulfates, chloride, and to a lesser extent, nitrates are
believed to be the result of roadsalt applications to the highway and
septic system impacts. In each case however, the high values were
significantly diluted as the city supply wells withdrew recharge water
from the other regions with lower concentrations. The City is
fortunate to have a relatively large undeveloped area near the well
field to provide dilution of contaminates originating in the developed
parts of the recharge area.
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http://digital.library.wisc.edu/1793/80393Type
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