Ground engineering · Groundwater & dewatering

Confined aquifer drawdown (Thiem & Cooper–Jacob) calculator

Drawdown at a distance and time using Cooper–Jacob, and steady Thiem discharge for comparison.

Standard: Thiem steady state · Cooper–Jacob transient

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Result	Value	Unit
u = r²S/(4Tt)	0.000
s = 2.3Q/(4πT) log(2.25Tt/(r²S))	4.40	m

Diagram for the worked example

u = r²S/(4Tt) = 30^2*1.000e-4/(4*300*2) = 3.750e-5
s = 2.3Q/(4πT) log(2.25Tt/(r²S)) = 2.3*20/1000*86400/(4*PI()*300)*LOG10(2.25*300*2/(30^2*1.000e-4)) = 4.4026 m

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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.