location of a managed well (Ashwaubenon #1) adja-
cent to a fixed well with a large pumping rate (Fort
Howard). Because the drawdown is limited in the man-
aged well, and the fixed well is substantially lowering
the water levels in that area, the nearby managed wells
cannot be pumped without violating the water-level
constraint in the nearby managed well.

Fox Cities Alternatives

     Optimization of ground-water withdrawals in the
Fox Cities indicates that nearly all of the projected
2030 demand can be met, while maintaining water lev-
els within 100 ft below the bottom of the confining
unit, if the municipalities in Central Brown County
convert to surface water (alternatives FC-1 through
FC-4, table 2). Of the 8 Fox Cities alternatives, FC-4
yields the most water, 10.3 Mgal/d. Even though this is
somewhat less than the projected demand of 12.4
Mgal/d, the entire shortfall occurs in the Heart-of-the-
Valley communities, which are closest to the Central
Brown County area. The communities in the Western
Towns meet their projected 2030 withdrawals for all
    For the Heart-of-the-Valley communities, com-
parison across the alternatives gives insight into the
importance of the various factors studied. For instance,
for the industrial wells fixed and high Brown County
water levels, managing the municipal wells (alterna-
tives FC-1 and -2) increases total yields from 3.9 to 4.1
Mgal/d. The increase is even greater for low Brown
County water levels, where managing the municipal
wells (alternatives FC-5 and -6) increases total yields
from 2.4 to 2.7 Mgal/d. Total yields from the industrial
wells in the Heart-of-the-Valley communities is zero
for all alternatives considered. Clearly the industrial
wells are located in an area where the water-level con-
straint is binding, and there is no excess capacity avail-
able for withdrawal. Thus whether the industrial wells
are fixed or managed is not important. The Brown
County water levels have the biggest impact on the
total yields for the Heart-of-the-Valley communities.
For example, for the cases where municipal and indus-
trial wells are managed, the total yields for high and
low Brown County water levels (alternatives FC-4 and
FC-8) are 4.3 and 2.9 Mgal/d, respectively.
    Examining the simulation results across the Fox
Cities alternatives reveals that the water levels in sev-
eral Western Town wells control much of the capacity
for withdrawals in the Heart-of-the-Valley communi-

ties. Because of differences in aquifer properties, some
of the Western Town wells are able to withdraw water
with a smaller resulting drawdown compared to the
Heart-of-the-Valley wells. With an overall objective of
maximizing total withdrawals, this results in the West-
ern Town wells withdrawing water until their demand
constraints are met; the remaining capacity in the sys-
tem is not sufficient to satisfy the Heart-of-the-Valley

Limitations of Simulation Results

    The steady-state version of the ground-water
model was used for all alternatives. The steady-state
option was chosen for simplicity and because it was
determined that 1990 water levels from the transient
model were already very close to water levels calcu-
lated for steady-state conditions using 1990 pumping
rates (Conlon, 1998). The differences between water
levels for 1990 transient and steady-state simulations
were within 2 ft near the city of Green Bay, and ranged
from 6 to 14 ft in the Fox Cities area. Comparisons
based on future pumping conditions also indicate that
transient water levels will be very close to steady-state
levels. Thus, if all of the conditions of the model
remain the same, the rates determined for a particular
simulation and the resulting water levels are the rates
that could be used in perpetuity.
    Water-level constraints were applied to drawdown
in a particular model cell, not to actual drawdown in
specific wells. Because a regional model is used with
rather coarse grid spacing and there are commonly
multiple wells within a single cell, it is not appropriate
to determine actual drawdown in the wells. The results
presented here can be used in general for planning pur-
poses and to evaluate implications of the various man-
agement alternatives. Simulations necessary to specify
the operation of individual wells would require more
detailed modeling with a finer grid spacing, and are
beyond the scope of this report.
    Because well loss is directly proportional to pump-
ing rate, spreading withdrawals among a group of wells
will greatly reduce the drawdown in the individual
wells. This effect is not reflected in the results pre-
sented in this report because the water-level constraints
were applied to drawdown in the model cells.
    For both the Brown County and Fox Cities simu-
lations, the results were controlled in part by water-
level constraints applied to either a single well or a few
wells in a small area. For the Brown County simula-

18  Optimization of Ground-Water Withdrawal in the Lower Fox River Communities, Wisconsin