OBJECTIVE
Evaluate the potential for ground-water contamination based on current
land use and the capture zones of current and proposed municipal supply
wells.
DESCRIPTION
Ground water is the primary source for drinking water supplies in Dane
County. Numerous wells throughout the county withdraw vast volumes of
water to meet existing community needs. At present many of these
communities are proposing development of new wells to meet the needs of
their growing populace.
Originating as precipitation at the surface, water that does not
evaporate or follow the process of evapotranspiration generally
percolates through near surface soil where it accumulates in porous
subsurface geologic materials. Rock or sediment which is saturated and
sufficiently permeable to transmit economical quantities of water to
wells is recognized as an aquifer. Much of the ground water withdrawn
from aquifers in Dane County originated as surface precipitation, hence
the awareness of many communities that surface activities can impact the
quality of future ground-water resources.
This project will use a ground-water model specifically designed for Dane
County to evaluate the capture zone of existing and proposed high
capacity municipal wells under a 100-year pumping scenario. A capture
zone essentially defines the path of influence created by a pumping well,
that is, a molecule of water within this path of influence would
theoretically be captured by the pumping well. A map will be made
delineating the capture zones and will be overlain with a county land use
map. Intersection of capture zones with land use areas designated as
industrial zones will be identified as potential source locations for
ground-water contamination. The end product will be a map showing areas
whose existing land use may potentially impact ground water resources.