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Apparent Velocity of Seepage is the velocity at which groundwater moves through the porous medium, as observed over a larger scale. It represents the macroscopic flow rate through the soil or rock matrix.
The calculator uses the Darcy's law formula:
Where:
Explanation: The apparent seepage velocity is directly proportional to both the coefficient of permeability and the hydraulic gradient, following Darcy's law for flow through porous media.
Details: Calculating seepage velocity is crucial for groundwater flow analysis, contaminant transport studies, foundation design, and the design of drainage systems in geotechnical and environmental engineering.
Tips: Enter the coefficient of permeability in m/s and the hydraulic gradient (dimensionless). Both values must be positive numbers greater than zero.
Q1: What is the difference between apparent velocity and actual velocity?
A: Apparent velocity is the macroscopic flow rate through the entire cross-section, while actual velocity accounts for the tortuous path through pore spaces and is typically higher.
Q2: How is coefficient of permeability determined?
A: It can be determined through laboratory tests (constant head or falling head tests) or field tests (pumping tests, slug tests).
Q3: What factors affect hydraulic gradient?
A: Hydraulic gradient is influenced by topography, groundwater recharge/discharge conditions, and the geometry of the aquifer system.
Q4: When is Darcy's law applicable?
A: Darcy's law applies to laminar flow through saturated porous media and is valid for Reynolds numbers less than 1-10.
Q5: What are typical values for coefficient of permeability?
A: Values range from 10⁻² m/s for gravel to 10⁻⁹ m/s for clay, depending on soil type and composition.