Fox River
Vernon Marsh
Lake Beulah
SArmy Lake
2 miles
Figure 3.9. Area where heads declined by 1 ft or more (gray) as a result of pumping with a
10% increase in the southern boundary fluxes only in the pumping layers (layers 8 and 9).
The green areas are surface water features. The yellow star is the location of the three
pumping wells near Vernon Marsh. The light blue star is the location of the well near Lake
Beulah. The affected area around Lake Beulah is much smaller compared to the area shown
in Fig. 3.7, though not as small as the area shown in Fig. 3.8.
An additional sensitivity analysis was run with 10% more flux coming through the
bottom boundary. The results were the same as the initial predictive model (Fig. 3.7),
indicating the heads are not sensitive to the bottom flux boundary. The model receives only
0.5% of inflow from the bottom boundary, while 36% enters the model from the side
boundaries, 44% enters from recharge at the surface, and 19.5% enters from rivers and lakes.
The effects on flows to the surface water features under the four scenarios are shown in Table
3.8.