FLOOD07651

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

98 GROUNDWATER PUMPING TESTS

Table 5.6. Database for Case Study 5.6

CASE STUDIES 99

Adjusted
Drawdown
(ft>
4.02
3.95
2.32
2.17
1.91
1.88
1.85
1.00
0.88
0.84
0.47

Match Pt. Coord. W(us,Beta) =' 0.1, 1/us = 10
s = 4.3 X 10-' .

t = 1.28 X 10'

T =' 1.146 X 10'(1.0 X 103)0.1/4.3 X 10-'
T = 266,511 gpd/ft

8, = 2.66 X 10'(0.1)1.28 X 10'/[2.693 X 103(4.0 X 104))
8, = 0.0316

Time After
Pumping
Started
(min>

1
2
3
4
5
6
7
8
9
10
15
20
30
40
50
60
70
80
90
100
150
200
300
400
500
600
700
800
900
1000
1480

WellS
Adjusted
Drawdown
IfU

0.09
0.22
0.30
0.36
0.39
0.42
0.44
0.46
0.47
0.48
0.51
0.53
0.56
0.60
0.66
0.70
0.75
0.80
0.83
0.87
1.01
1.13
1.26
1.37
1.42
1.54
1.60
1.66
1.70
1.74
1.91

Distance
llU

12
13
100
101
200
210
215
500
502
505
840

Distance-Drawdown Graph

Q = 1000 gpm, t = 1440 min, m = 100 ft

Match Pt. Coord. W(u) = 0.1, u =0.1,
s = 4.4 X 10-' r' = 4.1 X 10'

T = 1.146 X 10'(1.0 X 10')0.114.4 X 10-2
T = 260,454gpd/ft

8, = 2.60 X 10'(0.1)1.44 X 10'/[2.693 X 10'(4.1 X 105))
8, = 0.0339

The time-drawdown graph for observation well 5 and the
distance-drawdown graph are presented in Figures 5.7 and
5.8.
The average values of aquifer transmissivity, storativity,
specific yield, and PVIPH ratio are 260,000 gpd/ft, 0.0023,
0.032, and 1110, respectively. These values represent the
aquifer within a radius of about 4650 ft from the produc-
tion well. The specific yield is representative of the deposits
above the cone of depression and may not be representative
of the aquifer as a whole. Well storage capacity impacts
were negligible before 1 minute of pumping, and partial
penetration impacts were appreciable to a distance of 474 ft
from the production well and were taken into account in the
analysis. Delayed gravity yield impacts were appreciable
until 691 minutes after pumping started.
A step drawdown test was conducted in Case Study 5.7
on April 27, 1954, using a production well near Granite
City, Illinois (see Walton, 1962, pp. 63-64). The medium to
fine grained sand with some gravel aquifer is 106 ft thick.

8 = 2.79 X 105(1)9.0 X 10-1/(2.693 X 10'(4.0 X lO')j
8 = 0.00233

PvlPH = 1.0 X 104(3.0 X 10-1)/4.0 X 10'
PvlPH = 7.5 X 10-2 = 1/13