What is effective porosity vs total porosity?

Total porosity n_t includes dead-end pores. Effective (connected) porosity n_e is lower and represents actual flow paths. For flow calculations use effective porosity: sand 0.25-0.35, gravel 0.15-0.30.

How fast does groundwater typically flow?

Typical seepage velocities: gravel 0.3-30 m/day, sand 0.003-3 m/day, silt 10⁻⁶-0.003 m/day. This determines how long contaminants take to reach wells or surface water.

How is contaminant travel time calculated?

Travel time = L/v_s where L = distance, v_s = K·i/n. For a plume to travel 1 km in medium sand (v_s = 0.1 m/day): t = 1000/0.1 = 10,000 days ≈ 27 years. Account for retardation for sorbing contaminants.

Seepage Velocity Calculator

Calculate actual groundwater seepage velocity v_s = K·i/n, where n is effective porosity. Groundwater travel time = distance/v_s. Contaminant transport and wellhead protection zone delineation.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate actual groundwater seepage velocity v_s = K·i/n, where n is effective porosity. Groundwater travel time = distance/v_s. Contaminant transport and wellhead protection zone delineation. Use the seepage velocity result to inform your clinical assessment.

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Frequently Asked Questions

What is effective porosity vs total porosity?

How fast does groundwater typically flow?

How is contaminant travel time calculated?