In-Situ Testing & Geophysics

Drawdown Analyzer (Pumping Test)

Calculate aquifer Transmissivity and Storativity using Cooper-Jacob, and predict drawdown using the Theis well function.

ASTM D4106

Inputs

Demo

1. Pumping & Aquifer Parameters

Pumping Rate, Q (m³/day)

Observation Dist, r (m)

Ignore Early Points

Cooper-Jacob is only valid for large time.

Data (Time in min, Drawdown in m)

Results

Enter the pumping rate, observation distance and at least two time–drawdown readings above, or click a Demo preset.

Cooper-Jacob Formulation

Valid for small u = r²S / (4Tt) (typically u < 0.01). This implies it is valid for larger times or smaller distances.

T = 2.303 * Q / (4 * π * Δs)
S = 2.25 * T * t₀ / r²

About this calculator

This free pumping test analysis calculator runs entirely in your browser: what you enter is never uploaded. Use the calculation steps and the theory section to check the working, and print a calculation sheet with the inputs, results and formulae for your records.

Methods and references: ASTM D4106.

Topics: pumping test, drawdown, transmissivity, storativity, cooper-jacob, theis, hydrogeology, groundwater.

Engineering notice: Results are for preliminary estimation, screening and education. All inputs and outputs must be independently verified by a qualified professional engineer before use in any design or construction decision. Read the full disclaimer