Ground-water development in East St. Louis area, Illinois. Urbana, IL ...

of the drought and changes in river stage are taken
into consideration, water-level declines are directly proportional
to pumping rates. The water levels vary from
place to place within pumpage centers and from time to
time mostly because of the shifting of pumpage from
well to well, shifting of pumpage from pumpage centers
1 mile or more from the Mississippi River to pumpage
centers near the river, and variations in total well field
pumpage. At no location is there any apparent continuous
decline that cannot be explained by pumpage increases.
Thus, within a relatively short time after each
increase in pumpage, recharge directly from precipitation
and by induced infiltration of water in streams increased
in proportion to pumpage as hydraulic gradients
became greater and areas of diversion expanded.
Annual fluctuations of water levels in wells within
major pumping centers are generally less than 15 feet.
The average rate of decline during 1952-1956 was about
2 feet per year. The average rate of rise in the Granite
City area during the period 1957-1962 was about 2 feet
per year. The average rate of decline in the Monsanto
area during 1930-1962 was about 1.3 feet per year.
Figure 48.
Water levels in wells in National City area,
Figure 49.
Water levels in wells in Monsanto area
1955-1962
PIEZOMETRIC
SURFACE
In order to delineate areas of diversion and to determine
directions of ground-water movement in the East
St. Louis area, piezometric surface maps were made.
Figure 51 depicts the surface drainage system in 1900
and the estimated piezometric surface prior to heavy industrial
development. The piezometric surface sloped
from an estimated elevation of about 420 feet near the
bluffs to about 400 feet near the Mississippi River. The
average slope of the piezometric surface was about 3
feet per mile; however, the slope ranged from 6 feet per
mile in the Alton area to 1 foot per mile in the Dupo
area. The slope of the piezometric surface was greatest
near the bluffs. The general direction of ground-water
movement was west and south toward the Mississippi
River and other streams and lakes. The establishment of
industrial centers and the subsequent use of large quantities
of ground water by industries and municipalities
has lowered water levels appreciably in the areas of
heavy pumping.
From 1952 through 1956 water levels declined appreciably
in the East St. Louis area as the result of
drought conditions, low Mississippi River stages, and
record high ground-water withdrawals. Figure 52 shows
the piezometric surface in December 1956, when water
levels were at record low stages at many places.
The illustration shows clearly the cones of depression
in the piezometric surface which have developed
as the result of heavy pumping. It will be noted that a
considerable lowering has taken place in the piezometric
surface since 1900. In 1956 the deepest cone of depression
was in the Granite City area. Other pronounced
cones were centered in major pumping centers.
Figure 53 shows the piezometric surface in June
1961 after pumpage was reduced in the Granite City area.
The piezometric surface map for December 1956 is similar
in many respects to the piezometric surface map for
June 1961. Significant differences are that the cone of
depression in the Granite City area was much deeper
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