Coefficient Of Permeability Given Confined Aquifer Discharge Calculator

Coefficient of Permeability in Well Hydraulics Formula:

\[ KWH = \frac{Q}{\frac{2 \pi bw st}{\log\left(\frac{Rw}{r}, e\right)}} \]

Discharge (Q):

m³/s

Aquifer Thickness (bw):

Total Drawdown in Well (st):

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 is a crucial parameter in groundwater hydrology that quantifies the ability of an aquifer to transmit water.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ KWH = \frac{Q}{\frac{2 \pi bw st}{\log\left(\frac{Rw}{r}, e\right)}} \]

Where:

\( KWH \) — Coefficient of Permeability in Well Hydraulics (m/s)
\( Q \) — Discharge rate (m³/s)
\( \pi \) — Mathematical constant pi (≈3.1416)
\( bw \) — Aquifer Thickness (m)
\( st \) — Total Drawdown in Well (m)
\( Rw \) — Radius of Influence (m)
\( r \) — Radius of well (m)
\( e \) — Mathematical constant e (≈2.7183)

Explanation: This formula calculates the permeability coefficient based on well hydraulics principles, considering the geometric and flow characteristics of the aquifer system.

3. Importance of Coefficient of Permeability Calculation

Details: Accurate determination of permeability coefficient is essential for groundwater resource management, well design, contaminant transport studies, and predicting aquifer response to pumping.

4. Using the Calculator

Tips: Enter all values in appropriate units (meters for length, m³/s for discharge). Ensure all values are positive and the radius of influence is greater than the well radius for valid results.

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 10⁻² m/s for gravel, depending on soil type and composition.

Q2: How does aquifer thickness affect permeability?
A: Aquifer thickness directly influences the transmissivity of the aquifer, which is the product of permeability coefficient and aquifer thickness.

Q3: What factors can affect the accuracy of this calculation?
A: Well construction, aquifer heterogeneity, boundary conditions, and measurement errors can affect the accuracy of permeability calculations.

Q4: When is this formula most applicable?
A: This formula is particularly useful for confined aquifers with radial flow to a fully penetrating well under steady-state conditions.

Q5: How does drawdown relate to permeability?
A: Lower permeability results in greater drawdown for the same pumping rate, as water moves more slowly through the aquifer material.