Problem:
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 below 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.
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Pumping well A
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Observation well 1
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Observation well 2
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Distance from A (m)
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2.3
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10.7
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Hydraulic head (m a.d.l.)
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45.3
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46.5
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Measured flow (m3/day)
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184
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