FLOOD07651

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

86 GROUNDWATER PUMPING TESTS
Table 5.2. Database for Case Study 5.2
Time After Weill Time After Well 2
Pumping Adjuated Pumping Adjusted
Started Drawdown Started Drawdown
(min) (ft) (min) (ft)
5 1.00 2 4.60
6 1.19 3 4.97
7 1.25 4 5.32
8 1.43 5 5.65
9 1.58 6 5.91
10 1.72 7 6.08
12 1.94 8 6.20
15 2.32 9 6.33
18 2.64 10 6.50
20 2.85 15 7.62
25 3.26 20 8.21
30 3.61 25 8.75
40 4.42 30 9.23
50 5.00 40 10.02
60 5.51 50 10.55
71 6.12 60 11.25
80 6.50 70 11.74
90 6.91 80 12.21
100 7.28 90 12.54
152 8.91 100 12.80
195 9.90 150 14.35
254 11.15 195 15.38
300 fi.64 255 16.57
360 12.60 300 17.14
360 17.78

CASE STUDIES 87

locations of the image wells, and therefore the barrier
boundaries, cannot be determined with test data alone.
Logs of wells indicate that the aquifer occurs as a fill in a
buried valley in shale bedrock. Based on pumping test and
geologic data, the barrier boundaries were located at posi-
tions east and west of the production well. The boundaries
represent a rectangular section which is equivalenthydrau-
lically to the real aquifer system.
Calculations for the observation wells are as follows:

Observation Welll

Q '" 62 gpm, r = 165 ft, m = 8 ft
Match Pt. Coord. W(u) = 1.0, l/u = 1.0, s = 1.45 ft
t=2min

T = 1.146 X 10'(62) 1.0/1.45 T = 4900 gpdIft
S = 4.9 X 103(1.0)2/[2.693 X 1()3(165)'] S = 0.000134

Su = 1.0 ft,

tu = 44 min

of the second and third type curve traces were used to
determine the distances from the observation wells to the
second barrier boundary image well.
The distances from each observation well to the image
wells were scribed as arcs from the respective observation
wells. Theoretically, the arcs should intersect at common
points, but the real aquifer is not a vertically bounded aqui-
fer (as assumed in the image well theory), and as a result
the arcs and their intersections are dispersed. In addition,
only two observation wells are available, so that the exact

Wiuu) = 4.9 X 103(1.0)/[1.146 X 10'(62))
W(uu) = 0.6896

11;1 = 4.12 X 10-1

ru = ([4.9 X 103(44)4.12 X 10-'V
[2.693 X 103(1.34 X lO-'))}1f.!

ru = 496 ft

s" = 1.0 ft, t" = 154 min

W(u,,) = 0.6896, Ui2 = 4.12 X 10-1

r" "" ([4.9 X 103(154)4.12 X 10.1]1
[2.693 X 103(1.34 X 1O-4))}ln

r" = 928 ft

Observation Well 2

Q = 62 gpm, r = 20 ft, m = 8 ft

Match Pt. Coord. W(u) '" 1.0, l/u '" 100, s = 1.45
ft t =5.6 min