Geology Reference
In-Depth Information
The flow in gallons per minute equals the distance (
A
) in inches multiplied
by a constant
k
obtained from the following table.
Internal diameter
of pipe ('')
k
2.0
3.3
2.5
5.1
3.0
7.3
3.5
10.0
4.0
13.1
4.5
16.5
5.0
20.4
5.5
24.7
6.0
29.4
6.5
34.5
Approximate flow from pipe running full in gallons per minute
Horizontal Distance
(
A
)
Dia-
12
14
16
18
20
22
24
26
28
30
pipe
2
41
48
55
61
68
75
82
89
96
102
3
90
105
120
135
150
165
180
195
210
225
4
150
181
207
232
258
284
310
336
361
387
6
352
410
470
528
587
645
705
762
821
880
Minimum period of pumping test - at least 6 to 8 hrs or till a good
response of the Aquifer is achieved.
Preparation, Compilation and Analysis of Data
Time to be expressed in days
Water level to be reduced to draw down in metres
Either time-draw down or distance-draw down data
Correction of observed draw down for variation in barometric pressure,
changes in tidal height, rate of pumping changes in adjacent wells.
Type of aquifer
Suitable methods for analysis to be applied depending upon type of aquifer
The two important aquifer parameters in relation to groundwater flow are
the transmissivity (
T
) and the Storage Coefficient (
S
). Pumping tests are the
most practical and direct methods of determining these parameters. Some of
the constraints in performing these tests are, however, the cost towards
conducting the tests, and the availability of observation wells near the
