Leaky aquifers

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Lecture 17

• Leaky aquifers

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Review problem
At time t0 well A started pumping QA 2 cfs.
Well B started one day later with the same
Q. Estimate the time at which both wells
contribute equally to the drawdown at the
observation well.
A
B
400 ft
100 ft
o.w.
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Review problems
An aquifer test conducted in a confined aquifer
intersected by a no flow boundary (unknown
location) suggested that the drawdown at
an observation well 200 ft from the pumping well
after 250 minutes to be 16 ft, instead it was 18
ft. Estimate the distance from the well to the
boundary. At 10 minutes the drawdown was 2 ft
and it was assumed that the influence of the
boundary at that early time is negligible,
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Governing equation
Consider shown volume element
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Steady radial flow in leaky aquifer
The solution is given by
Modified Bessel Function of second kind of order
zero
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Transient case leaky aquifer
GPDA
Solution
W(u,beta) Hantush well function
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Hantush well function
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