Coefficient Of Permeability When Discharge Is Considered Calculator

Formula Used:

\[ k = \frac{q \times L_{stream}}{(h_o - h_1) \times b} \]

Discharge per Unit Width of Aquifer (q):

m³/s

Length between Upstream and Downstream (L):

Piezometric Head at Upstream End (hₒ):

Piezometric Head at Downstream End (h₁):

Aquifer Thickness (b):

Coefficient of Permeability (k):

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1. What is the Coefficient of Permeability?

The Coefficient of Permeability refers to the rate of flow of water under laminar flow conditions through a unit cross-sectional area of a porous medium under a unit hydraulic gradient. It is a key parameter in hydrogeology and civil engineering for analyzing groundwater flow.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ k = \frac{q \times L_{stream}}{(h_o - h_1) \times b} \]

Where:

\( k \) — Coefficient of Permeability (m/s)
\( q \) — Discharge per Unit Width of Aquifer (m³/s)
\( L_{stream} \) — Length between Upstream and Downstream (m)
\( h_o \) — Piezometric Head at Upstream End (m)
\( h_1 \) — Piezometric Head at Downstream End (m)
\( b \) — Aquifer Thickness (m)

Explanation: This formula calculates the permeability coefficient based on the discharge through an aquifer section and the hydraulic gradient.

3. Importance of Permeability Calculation

Details: Accurate permeability estimation is crucial for groundwater flow modeling, well design, contaminant transport studies, and designing effective drainage systems in geotechnical engineering projects.

4. Using the Calculator

Tips: Enter all values in appropriate units. Ensure that upstream head is greater than downstream head for valid calculation. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of permeability coefficients?
A: Permeability coefficients vary widely from 10⁻¹² m/s for clay to 10⁻¹ m/s for gravel, depending on the soil or rock type.

Q2: How does permeability affect groundwater flow?
A: Higher permeability allows faster groundwater movement, while lower permeability restricts flow and can create confined aquifers.

Q3: What factors influence permeability?
A: Grain size distribution, porosity, particle shape, packing arrangement, and degree of saturation all affect permeability.

Q4: How is this different from hydraulic conductivity?
A: Coefficient of permeability and hydraulic conductivity are often used interchangeably, though hydraulic conductivity specifically refers to water flow through porous media.

Q5: When should field measurements be used instead of calculations?
A: Field tests like pumping tests or permeameter tests provide more accurate results for complex geological conditions or when laboratory samples cannot represent in-situ conditions.