(11C) Transmissivity

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An extract (pages 138-140) from GROUND-WATER RESOURCES OF SOUTHERN COMANCHE COUNTY, SOUTHWESTERN OKLAHOMA, MS thesis UoP, BENJAMIN BETKE GREELEY, 1986 (294 pgs)

CALCULATOR PROGRAM FOR HEWLETT-PACKARD HP-11C
A calculator program written by Patterson (1984, p.142) for the Texas Instruments TI-59 and modified for the Hewlett-Packard HP-11C calculates transmissivity, T, from specific capacity, Q/s, according to a formula by Walton (1970, p.315):

T = Q/s [ 264 log ( T t / 2693 r2 S ) - 65.5 ]
where
T = transmissivity, gpd/ft.,
Q/s = specific capacity, gpm/ft.,
Q = discharge, gpm,
s = drawdown, ft.,
S = storativity of a confined aquifer or specific yield of an unconfined aquifer, fraction,
r = nominal well radius, ft.,
t = duration of pumping, minutes.

Enter the program into calculator memory with the following:
g P/R Program mode
f LBL A Labels and defines beginning of program; A = any alphabetic or numeric key.
RCL 2 pumping duration, t
× multiplication
RCL 1 well radius, r
g x²
RCL 0 storativity, S, or specific capacity, Sy
× multiplication
2693
×
÷ division
g LOG
264
×
65.5
- subtraction
RCL 3 specific capacity, Q/s
×
g RTN End of program

To run the program store the following parameters in the registers, Rn:
R0: S or Sy
R1: r
R2: t
R3: Q/s

Enter (key in) any initial transmissivity value and begin the program with the keystrokes f A. The "running" display flashes until a calculated T value is shown. Enter this transmissivity and subsequent values with the keystrokes f A until the final transmissivity equals the initial transmissivity. The permeability is the ratio of the transmissivity to the saturated thickness:
K = T/b
where
K = permeability, gpd/ft²,
T = transmissivity, gpd/ft.,
b = saturated thickness, ft.

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