Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

Q

Constant pumping discharge in cubic meters per day.

T

Transmissivity in square meters per day.

t

Duration of pumping in days before shutdown.

t'

Time since pumping stopped in days.

Compute Theis recovery residual drawdown in meters as Q / (4 pi T) times the natural log of pumping duration over time since recovery began (days). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

s'

Residual drawdown in meters.

• Aquifer calculations assume a geometry, boundary condition, flow regime, hydraulic properties, well construction, and observation response. Heterogeneity, anisotropy, leakage, storage, partial penetration, recharge, and pumping history can invalidate simple analytical solutions.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

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