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PART 12 Aquifer pumping tests - Dr. M. Zreda - University of Arizona

PART 12 Aquifer pumping tests - Dr. M. Zreda - University of Arizona

PART 12 Aquifer pumping tests - Dr. M. Zreda - University of Arizona

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<strong>Aquifer</strong> <strong>pumping</strong> <strong>tests</strong> 89<br />

Boundary conditions:<br />

BC1: Prescribed head at the lake:<br />

h = H at r = R<br />

BC2: Prescribed flux at the well (= <strong>pumping</strong> rate Q):<br />

Q = K(2πrb)(∂h/∂r) at r = r w (well radius)<br />

or, after rearranging and putting T = Kb:<br />

---------<br />

Q<br />

r<br />

2πT<br />

h ∂<br />

= -----<br />

∂r<br />

Solution:<br />

Integrate once:<br />

Use BC2: C 1 = Q/(2πT)<br />

Rearrange by grouping r terms together<br />

Integrate<br />

Use BC1:<br />

r h ∂<br />

----- = C1 ∂r<br />

∂r<br />

∂h = C1---- r<br />

Q<br />

h = C1lnr + C2 = --------- lnr + C2 2πT<br />

C 2<br />

Q<br />

= H – --------- lnR<br />

2πT<br />

Final solution for h becomes<br />

h – H<br />

---------<br />

Q r<br />

=<br />

⎛ln- ⎞<br />

2πT ⎝ R⎠<br />

Thiem equation<br />

Hydrogeology, 431/531 - <strong>University</strong> <strong>of</strong> <strong>Arizona</strong> - Fall 2007 <strong>Dr</strong>. Marek <strong>Zreda</strong>

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