REPORT OF INVESTIGATIONS No. 38 15
tween the aquifer and the confining bed under a unit head difference.
The pumping tests were analyzed by using a family of type curves developed by Cooper (1963). The type curves are based on a formula developed by Hantush and Jacob (1955) for the drawdown around a pumped well in an artesian aquifer whose confining bed leaks water to the aquifer at a rate proportional to the drawdown.
The first test was made by pumping well 9S and observing the drawdown in wells 9N and 10. Wells 9S, 9N, and 10 tap both the first and second artesian aquifer. The drawdowns were plotted against the time since the pumping started divided by the distance of the observation well from the pumping well. The plots are shown in figure 5. From the drawdown observed in well 9N the coefficient of transmissibility was computed to be 5,600 gpd per ft (gallons per day per foot); the coefficient of storage, 8.7 x 10-5; and the coefficient of leakage, 1.3 x 10-3 gpd per ft". From the drawdown observed in well 10, the coefficient of transmissibility was computed to be 6,100 gpd per ft; the coefficient of storage, 1.1 x 10-4; and the coefficient of leakage, 1.4 x 10-3 gpd per ft3.
. In minutes per It
F:."~~0" s 04i- OZIT' TyeC Crves 2
. ... 005
. 1e,0025 Abse
00
sta0 0
%0 0.
Obseved dataoY'"uv 
0.1 M och Point u"E XPNL ANA TION S P L AN I N T 6.100 Qpd per It
L.0 uv)O s 60
0-'428.8 ULu0) ID"l
*u 10" C3
1,8 a -lOU2f
4T.1 0.I
".01I .-A! -Motch Po;nt .
ull'l10 Lt' ,l' 4.gxlO'-rnnuies per Mel
42C10,4 minules per t2 I 4 i0r nues per ft2
p!~~4 12 1. x! 1v 0*4l3 gad per It?
4T- i .3 Io3gpd per It" -4 14 o pd per t
4T v.,10 m ..035I
v:0 025 f148 ft
r 3. IL I Inn ,,..I,ni I I I, "I I I I I II1! 0 10' s ,10-4 10*3 I10-2 I 01 % r', in minutes per lel Figure 5. Logarithmic plots of the drawdown in well 9N and in well 10 versus t/r2.