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For multi-stage or step-drawdown tests. Save each stage as separate record.
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Pumping Well & Aquifer
m³/day
meters (saturated thickness)
meters (effective well radius, for apparent S only)
⚠ Note on Storativity from pumping well data: Jacob's S computed from drawdown measured at the pumping well is an apparent S — biased by well losses, wellbore storage, partial penetration, and skin effects. For a reliable (true) S, add observation well data below. CGWB / NAQUIM practice requires at least one observation well at a documented radial distance.
Pumping Well — Drawdown Data (at pumping well)
Paste Data: Copy two columns (Time in min, Drawdown in m) from Excel/CSV and paste below.
Exclude early-time points where u ≥ 0.01. Blank = fit all points.
Exclude late-time points affected by boundaries. Blank = fit all points.
💡 Interactive fitting: On the Pumping Well Analysis chart, click any data point to toggle exclude/include. Excluded points appear as gray open circles, fitted points as blue filled. Combine with Start/End time window above for precision control.
Observation Wells — for True Storativity (S)
Add one or more observation wells. Each has its own radial distance from the pumping well and its own time–drawdown series. Jacob's analysis on each obs well yields a reliable T and true S.
Recovery Data (at pumping well)
Paste Data: Copy three columns (Pumping Time t, Recovery Time t', Residual Drawdown s').
Regression Results
Aquifer Parameters
Per-Observation-Well Jacob's Analysis
Storativity reported here is the true SRELIABLE — computed from drawdown measured at a known radial distance from the pumping well. If multiple obs wells are given, an average T and S is also reported.
Recovery Parameters
Step-Drawdown Test — Data
Multi-step pumping test: Well pumped at successive constant rates (typically 3–5 steps). Record stabilized drawdown at end of each step. Tool fits Jacob s = BQ + CQ² (linear/quadratic) and Rorabaugh s = BQ + CQⁿ (non-linear, fits n).
Jacob's Method — s = BQ + CQ²
Divide both sides by Q: s/Q = B + CQ (linear). Plot s/Q vs Q → intercept = B (aquifer loss coefficient), slope = C (well loss coefficient).
Rorabaugh Method — s = BQ + CQⁿ
Non-linear fit over B, C, n. Exponent n typically 2 (Jacob) to 3.5 (severe turbulent well loss). Higher n → greater well-loss component.
Well Efficiency & Step-Wise Breakdown
Walton (1962) criteria for C (Jacob well-loss coefficient):
C < 0.5 properly designed |
0.5 – 1.0 mild clogging |
1.0 – 4.0 severe clogging |
> 4.0 very poor, hard to restore
Analysis Method for Summary & Exports
Controls which T, S, K appear as "Best" below and in Excel/Word exports.
Obs wells preferred per CGWB/NAQUIM. Pump-well fallback if no obs data.