Ein Auja — live karst recession calibration

Fit a karst reservoir model to real measured spring discharge. Drag the parameters onto the data, or run gradient descent and watch it converge — or, with too big a step, miss.

עוג'ה · spring id 45350 · Israel Hydrological Service / Water Authority · pulled live via data.gov.il · current-meter era 1988–1990

RMSE

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R²

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τ = 1/α

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Q₀ (peak, L/s)560

α — fast conduit (1/day)0.0060

two-reservoir (fast conduit + slow matrix)

learning rate0.15

Gradient descent minimises log-space error. Nudge the learning rate past ~1.5 and watch the estimate overshoot and blow up — the classic miss-the-target failure, live.

Q(t)=Q₀·e^−αt real fit α≈0.0103/d τ≈98 d turnover R²≈0.985