FLOOD07651

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

94 GROUNDWATER PUMPING TESTS

CASE STUDIES 95

Table 5.5. Dalabase for Case Sludy 5.5

observation wells in the upper aquitard. Calculated val-
ues of aquifer transmissivity and storativity and average
lower aquitard vertical hydraulic conductivity and
storativity are 130,000gpdlft, 1.11 X 10-', 2.88 X 10-'
gpdlsq ft, and 6.0 X 10-" respectively.
Drawdown data for the aquifer and aquitard observation
wells were used to determine values of the ratio sjs at
times after the effects of pumping reached aquitard obser-
vation wells. Values of vertical hydraulic conductivity cal-
culated with ratios and Table E.5 in Appendix E and
assigned to the bottom 21 ft of the upper aquitard, bottom
11 ft of the upper aquitard, and top 6 ft of the lower
aquitard are 2.45 X 10-', 5.85 X 10-', and 4.17 X 10-',
respectively. Calculations for the aquifer observation well
and lower aquitard observation well are as follows:

Time After
Pumping Starled
(min)

1
3
12
25
40
70
100
240
510
860
1210
2880
4700
9200

Time After
Pumping Starled
(min)
510
1210
2880
4700
9200

Aquifer
Adjusled Drawdown
(ft)

2.59
3.61
4.81
5.36
5.65
6.03
6.31
7.12
7.73
8.02
8.29
8.96
9.43
9.81

Lower Aquitard
Adjusled Drawdown
(ft)

0.02
0.07
0.21

2.33

4.82
5.61

6.14

UpperAquitard
Adjusted Drawdown
(fl)

Aquifer Observation Well

~wer Source Bed
Adjusted Drawdown
(ft)

0.06
0.72
1.98

Q = 1000 gpm,

r = 100 ft,

m=93ft,

.m" == 30

3.23

0.02
1.17

Gamma = 0.005

W(u,Gamma) = 0.1, lIu = 1000.
t == 23 min

T = 1.146 X 10'(1.0 X 10')1.0 X 10-1lS.S X 10-'
T = 1.30 X 10' gpdlft

S = 1.3 X 10'(1.0 X 10-3)23/[2.693 X 103(1.0 X 10')]
S = 1.11 X 10-'

s = 0.088,

was 1000 gpm. Time-drawdown data for the aquifer obser-
vation well located 100 ft from the production well and data
for aquitard observation wells for selected times are pre-
sented in Table 5.5.
The aquifer time-drawdown curve was matched to the
appropriate model 4 type curve (Figure F,5 in Appen-
dix F) and match point coordinates and the selected
value of Gamma were used to calculate aquifer transmis-
sivity and storativity and the vertical hydraulic conduc-
tivity of the lower aquitard. Particular attention was
given to time-drawdown data before the effects of pump-
ing reached the bottom of the lower aquitard and the

P, = 2.5 X 10-'(16)1.3 X 10'(1.11 X 10-')301
{(1.0 X 10'(6.0 X 10")]

P, = 2.88 X 10-2 gpdlsq ft