Groundwater Flow — Darcy's Law, Aquifer & Well Drawdown

Explore how groundwater moves through permeable rock using Darcy's Law. Visualise hydraulic head, equipotential lines, flow paths, and the cone of depression around pumping wells.

Aquifer type:

Cross-section view — click on aquifer to add/remove a pumping well

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Darcy flux q (m/d)

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Head difference Δh (m)

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Drawdown s_w (m)

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Seepage velocity (m/d)

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Radius of influence (m)

Hydraulic Conductivity K (m/d) 10

Hydraulic Gradient i 0.010

Pumping Rate Q (m³/d) 500

Porosity n 0.25

Aquifer thickness b (m) 20

Recharge rate (mm/yr) 200

Unconfined Aquifer: Water table is free to rise and fall. Darcy's Law: q = −K·(dh/dl). Water flows from high hydraulic head to low. Drawdown at well: h²−h_w² = (Q/πK)·ln(r/r_w) (Dupuit–Thiem equation).

About Groundwater Flow

Darcy's Law (1856): q = −K·(dh/dl) — specific discharge q (m/d) = hydraulic conductivity K × hydraulic gradient. Seepage velocity v = q/n (n = porosity).

Unconfined aquifer: Bounded above by the water table (atmospheric pressure). Most shallow aquifers are unconfined.

Confined aquifer: Saturated zone bounded above by an impermeable layer (aquitard). Hydraulic head can be above the top of the aquifer (artesian conditions).

Well hydraulics (Dupuit–Thiem): Steady-state drawdown in confined aquifer: h−h₀ = Q/(2πKb)·ln(r₀/r). In unconfined: h²−h₀² = Q/(πK)·ln(r₀/r).

Hydraulic conductivity K: gravel 10–1000 m/d; sand 1–100 m/d; silt 0.001–0.1 m/d; clay <0.0001 m/d.