Coefficient Of Permeability Given Discharge In Confined Aquifer Calculator

Coefficient of Permeability in Well Hydraulics Formula:

\[ KWH = \frac{Q}{\frac{2\pi b_p(b_w - h_{well})}{\ln\left(\frac{R_w}{r}\right)}} \]

Discharge (Q):

m³/s

Aquifer Thickness During Pumping (bₚ):

Aquifer Thickness (b𝓌):

Depth of Water in Well (h𝓌ₑₗₗ):

Radius of Influence (R𝓌):

Radius of Well (r):

Coefficient of Permeability (KWH):

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1. What is Coefficient of Permeability in Well Hydraulics?

The Coefficient of Permeability in Well Hydraulics describes how easily a liquid will move through the soil. It's a critical parameter in groundwater studies and well design, indicating the soil's ability to transmit water.

2. How Does the Calculator Work?

The calculator uses the well hydraulics formula:

\[ KWH = \frac{Q}{\frac{2\pi b_p(b_w - h_{well})}{\ln\left(\frac{R_w}{r}\right)}} \]

Where:

\( KWH \) — Coefficient of Permeability (m/s)
\( Q \) — Discharge rate (m³/s)
\( b_p \) — Aquifer thickness during pumping (m)
\( b_w \) — Aquifer thickness (m)
\( h_{well} \) — Depth of water in well (m)
\( R_w \) — Radius of influence (m)
\( r \) — Radius of well (m)
\( \pi \) — Mathematical constant pi (≈3.1416)
\( \ln \) — Natural logarithm function

Explanation: This formula calculates the soil's permeability coefficient based on pumping test data from a confined aquifer.

3. Importance of Permeability Calculation

Details: Accurate permeability estimation is crucial for designing efficient well systems, predicting groundwater flow, managing aquifer resources, and environmental impact assessments.

4. Using the Calculator

Tips: Enter all values in consistent units (meters and m³/s). Ensure proper well test measurements are used as inputs. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for permeability coefficients?
A: Permeability varies widely by soil type: gravel (10⁻¹-10⁻² m/s), sand (10⁻³-10⁻⁵ m/s), silt (10⁻⁶-10⁻⁸ m/s), clay (10⁻⁸-10⁻¹¹ m/s).

Q2: How does this differ from unconfined aquifer calculations?
A: Confined aquifer formulas account for the constant aquifer thickness, while unconfined aquifer calculations consider the water table drawdown.

Q3: When should pumping tests be conducted?
A: Pumping tests should be conducted during stable hydrological conditions, typically avoiding extreme wet or dry periods that might affect results.

Q4: What affects permeability measurements?
A: Soil composition, compaction, saturation level, temperature, and testing methodology can all influence permeability measurements.

Q5: How accurate are these calculations?
A: The formula provides good estimates for homogeneous, isotropic confined aquifers. Complex geological conditions may require more sophisticated modeling.