Falling Head Permeability Calcs

Question 1

Is the formula typically provided for this question?

Answer 1

Yes, no need to learn it by heart.

Question 2

What is ‘a’ and how is it calculated?

Answer 2

The cross-sectional area of the standpipe

( Pi x standpipe dia. ^2) / 4

Question 3

What is ‘A’ and how is it calculated?

Answer 3

Cross-sectional area of the sample?

( Pi x sample dia. ^2 ) / 4

Question 4

What is ‘L’ ?

Answer 4

The length of the sample

Question 5

Using the constant values, a constant multiplication factor can be calculated, what is the remaining equation?

Answer 5

k = constant value x

( ln (h1 / h2) ) / (t2 - t1)

Question 6

What is (t2 - t1) equal to? Units?

Answer 6

The time onterval in seconds

Question 7

What units should the answer typically be presented in?

What is the conversion factor from mm/s to the preferred units?

Answer 7

m/s

x 10 ^-3

Question 8

In an unconfined aquifer, what is the value ‘q’ and what are the units?

What should ‘q’ be converted to and what formula is used?

Answer 8

q = flow rate in m^3 / hour

Should be converted to m^3 / seconds

This is done by dividing the original value by (60 x 60), or 3600.

Question 9

What is ‘log e’ equal to in the calculator?

Answer 9

ln button

Question 10

What is r1?

What is r2?

What are the units?

Answer 10

r1 = the smallest horizontal distance, to h1

r2 = the largest horizontal distance, to h2

Units are meters, m

Question 11

What is h1?

What is h2?

What are the units?

Answer 11

h1 = smallest height, equal to total height - values down to the mark

h2 = largest height, equal to total height - values down to the mark

Units are meters, m

Question 12

What are the end units of ‘k’?

Answer 12

m / s