Groundwater Flow Calculator
Compute groundwater discharge using Darcy's Law: Q = K × i × A, with unit conversion and result breakdown.
Use the Groundwater Flow Calculator
Darcy's Law Inputs
Q = K × i × A
Common values: gravel 10⁻² m/s, sand 10⁻⁴ m/s, clay <10⁻⁸ m/s
Dimensionless — head difference / flow path length (Δh / L)
Area perpendicular to the direction of flow
Typical K Values
| Material | K (m/s) |
|---|---|
| Gravel | 10⁻² |
| Coarse sand | 10⁻⁴ |
| Fine sand | 10⁻⁶ |
| Silt | 10⁻⁹ |
| Clay | 10⁻¹¹ |
Click a row to use that K value.
Enter values on the left and click Calculate
Groundwater Discharge (Q)
—
m³/s
—
m³/day
—
L/s
Parameter Summary
Hydraulic Conductivity (K)
—
Hydraulic Gradient (i)
—
Cross-sectional Area (A)
—
Darcy Velocity (q = Q/A)
—
Formula Breakdown
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Summary
This tool calculates groundwater discharge (Q) using Darcy's Law: Q = K × i × A, where K is hydraulic conductivity, i is the hydraulic gradient, and A is the cross-sectional area perpendicular to flow. It is essential for hydrogeology, civil engineering, and environmental science applications. Results are shown in cubic meters per second, cubic meters per day, and liters per second.
How it works
- Enter the hydraulic conductivity (K) of the aquifer material and select its unit (m/s, m/day, cm/s, or ft/day).
- Enter the hydraulic gradient (i), which is the head difference divided by the flow path length (dimensionless).
- Enter the cross-sectional area (A) perpendicular to the flow direction and choose the unit (m², cm², or ft²).
- Click "Calculate" to apply Darcy's Law: Q = K × i × A.
- View the discharge result in multiple units along with a parameter summary.
Use cases
- Estimate aquifer discharge rates for water supply planning.
- Assess contaminant transport speed through saturated soil.
- Design dewatering systems for construction sites.
- Size drainage structures and groundwater extraction wells.
- Validate field pump tests against theoretical Darcy predictions.
- Teach hydrogeology concepts in academic settings.
- Support environmental impact assessments for landfills or spills.
- Calculate seepage rates through earth dams and embankments.
Frequently Asked Questions
Last updated: 2026-06-04 · Reviewed by Nham Vu