Coefficient Of Permeability When Interference Among Well Is Present Calculator

Coefficient of Permeability Formula:

\[ K = \frac{Q}{\frac{2\pi b_p (b_w - h_w)}{\ln\left(\frac{R^2}{r'B}\right)}} \]

Discharge (Q):

m³/s

Aquifer Thickness During Pumping (bₚ):

Aquifer Thickness (b_w):

Depth of Water (h_w):

Radius of Influence (R):

Radius of Well (r'):

Distance Between Well (B):

Coefficient of Permeability (K):

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1. What is Coefficient of Permeability?

The coefficient of permeability (K) of soil describes how easily a liquid will move through the soil. It is a crucial parameter in environmental engineering for groundwater flow analysis and well interference studies.

2. How Does the Calculator Work?

The calculator uses the permeability formula:

\[ K = \frac{Q}{\frac{2\pi b_p (b_w - h_w)}{\ln\left(\frac{R^2}{r'B}\right)}} \]

Where:

\( K \) — Coefficient of permeability (m/s)
\( Q \) — Discharge rate (m³/s)
\( b_p \) — Aquifer thickness during pumping (m)
\( b_w \) — Aquifer thickness (m)
\( h_w \) — Depth of water in well (m)
\( R \) — Radius of influence (m)
\( r' \) — Radius of well (m)
\( B \) — Distance between wells (m)
\( \pi \) — Mathematical constant (3.14159)
\( e \) — Natural logarithm base (2.71828)

Explanation: This formula accounts for interference effects between wells and provides the permeability coefficient based on pumping test data.

3. Importance of Permeability Calculation

Details: Accurate permeability calculation is essential for designing groundwater extraction systems, predicting contaminant transport, and managing aquifer resources effectively.

4. Using the Calculator

Tips: Enter all values in appropriate units (meters for lengths, m³/s for discharge). Ensure all values are positive and physically meaningful (aquifer thickness > water depth).

5. Frequently Asked Questions (FAQ)

Q1: What is well interference?
A: Well interference occurs when multiple wells are close enough that their cones of depression overlap, affecting each other's performance and water extraction rates.

Q2: What are typical permeability values for different soils?
A: Clay: 10⁻⁸-10⁻¹⁰ m/s, Silt: 10⁻⁵-10⁻⁸ m/s, Sand: 10⁻³-10⁻⁵ m/s, Gravel: 10⁻¹-10⁻³ m/s.

Q3: When is this formula most applicable?
A: This formula is particularly useful for confined aquifers with multiple pumping wells where interference effects need to be considered.

Q4: What are the limitations of this approach?
A: The formula assumes homogeneous, isotropic aquifer conditions and may not accurately represent complex geological formations or anisotropic flow conditions.

Q5: How does well spacing affect permeability calculations?
A: Closer well spacing increases interference effects, which must be properly accounted for in the permeability calculation to avoid underestimating the true aquifer permeability.