A sample of drill core collected from an unconfined sandstone aquifer was tested using a constant head permeameter with a radius of 3cm at 20°C and provided the following data:
Flow rate = 0.18 cm3/min
Distance between manometers = 5 cm
Difference in head between manometers = 2.8 cm
A well in the same aquifer was pumped to a steady state, and the following information measured in a series of observation wells: (refer to attachments)
- Calculate the hydraulic conductivity of the rock sample.
- Use the data from the well pumping test to calculate the hydraulic conductivity of the aquifer as a whole.
- Suggest possible reasons for the differences in the results of your two calculations, and discuss the relative advantages and disadvantages of field and laboratory permeability tests.
Calculate the hydraulic conductivity of the rock sample.
Q= flow rate, K= hydraulic conductivity, i= hydraulic gradient = change in hydraulic head/change in distance, A = cross sectional areas
(2) A= r^2pi
A = (3 cm)^2 x pi = 28.27 cm^2
rearranging equation (1), isolate for K, hydraulic conductivity
(3) K = Q/iA
K = 0.18 cm3/min / (2.8cm/5cm)*28.27 cm^2
K = 0.0114 cm/min
Use the data from the well pumping test to calculate the hydraulic conductivity of the ...
The distances between manometers for hydraulic conductivity is examined.