FLOOD07651

• County: Statewide
• Basin: Statewide
• Title: Groundwater Pumping Tests: Design and Analysis
• Date: 12/1/1997
• Floodplain - Doc Type: Educational/Technical/Reference Information

96 GROUNDWATER PUMPING TESTS

CASE STUDIES 97

lO.oo

O. OJ
1

10 100 1000

Time After Pumping Started
Time-drawdown graphs for Case Study 5.5.

10000
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miles southeast of the corporate limits of the city of
Lawrenceville, Illinois (Prickett, 1965, pp. 5-14). Well logs
indicate that the stratified aquifer consists of 100 ft of fine
to medium sand with some coarse sand and much gravel.
The 16-in.-diameter production well screen was in the lower
25 ft of the aquifer; observation wells I, 3, 4, 6,7, 8, 9, 10,
and 11 have short screens in the upper 20 ft of the aquifer,
and observation wells 2 and 5 were screened near the
aquifer base. Distances to these observation wells from the
production well were 12, 13, 100, 101, 200, 210, 215, 500,
502, 505, and 840 ft, respectively. Pumping was started at
8:38 a.m. on May 17 and was continued for a period of 24
hours at a constant rate of 1000 gpm until 9:10 a.m. on. May
18. Time-drawdown data for observation well 5 and
distance-drawdown data at the end of the test, adjusted for
dewatering and partial penetration impacts, are presented
in Table 5.6.
The time-drawdowncurve for observation well 5 was
found to be analogous to the Beta == 0.3 model 6 type curve
{Figures F.6 and F.7 in Appendix Fl. Match point
coordinates and the selected Beta value were used to
calculate aquifer transmissivity, storativity, specific yield,
and PV/PH ratio. The model 1 type curve (Figure F.2 in
Appendix Fl was matched to the distance-drawdown curve,
and match point coordinates were used to calculate aquifer
transmissivity and specific yield. Calculations are as
follows:

.....
L&..
c:
..
.g
lit
o
d

0.10

lower

^qu itord
Observation
lie II

Upper
Aquitord

Aquifer ObservQtion lIell

I. 00

Figure 5.6.

Lower Aquitard Observation Well

r = 81 ft, Z = 6 ft, t = 80 min, s, = 7.8 X 10' ft
s =6.6 ft, . sjs = 7.8 X 10"/6.6, sjs = 1.18 X 10"
u= 2.693 X 103(6.56 X 103)1.11 X 10"/(1.3 X 105(80)]
u = 1.89 X 10'" 1/u, .. 3.44 X 10.1
P, = 2.693 X 103(36)3.44 X 10"(1.0 X 10")/80
Pc == 4.17 X 10" gpdlsq ft

Time-drawdown graphs for observation wells are presented
in Figure 5.6.

Observation Well 5

A pumping test was conducted in Case Study 5.6 on May
17 and 18, 1950, using a group of wells located about 4

Q = 1000 gpm, r = 200 ft, m = 100 ft

Match Pt. Coord. W(uAoBeta) '" 0.1, 1/uA '" 1.0
s= 4.1 X 10"

t = 9.0 X 10-1 Beta = 3.0 X 10.1

T = 1.146 X 10'(1.0 X 103)0.1/4.1 X 10"
T = 279,512 gpd/ft

WATER TABLE AQUIFER SYSTEM