Coefficient Of Permeability Given Discharge And Length Of Strainer Calculator

Formula Used:

\[ KWH = \frac{Q}{\frac{2.72 \times Stw \times (lst + \frac{Stw}{2})}{\log\left(\frac{Rw}{r}, 10\right)}} \]

Discharge (Q):

m³/s

Total Drawdown in Well (Stw):

Strainer Length (lst):

Radius of Influence (Rw):

Radius of Well (r):

Coefficient of Permeability (KWH):

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1. What is the Coefficient of Permeability?

The Coefficient of Permeability in Well Hydraulics describes how easily a liquid will move through the soil. It's a crucial 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 formula:

\[ KWH = \frac{Q}{\frac{2.72 \times Stw \times (lst + \frac{Stw}{2})}{\log\left(\frac{Rw}{r}, 10\right)}} \]

Where:

\( KWH \) — Coefficient of Permeability (m/s)
\( Q \) — Discharge rate (m³/s)
\( Stw \) — Total Drawdown in Well (m)
\( lst \) — Strainer Length (m)
\( Rw \) — Radius of Influence (m)
\( r \) — Radius of Well (m)

Explanation: This formula calculates the soil's permeability coefficient based on well hydraulic parameters and pumping test data.

3. Importance of Permeability Calculation

Details: Accurate permeability calculation is essential for designing efficient well systems, predicting groundwater flow, and managing water resources effectively.

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.

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.

Q2: How does strainer length affect permeability calculations?
A: Longer strainers typically result in higher effective permeability as they provide more surface area for water entry.

Q3: What is the radius of influence?
A: The distance from the well center to where the drawdown curve meets the original water table level.

Q4: When is this formula most applicable?
A: This formula is particularly useful for unconfined aquifers and well hydraulic analysis during pumping tests.

Q5: What are the limitations of this calculation?
A: The formula assumes homogeneous aquifer conditions and may not be accurate for complex geological formations or anisotropic soils.