Coefficient Of Transmissibility Given Confined Aquifer Discharge With Base 10 Calculator

Coefficient of Transmissibility Formula:

\[ T = \frac{Q}{\left(\frac{2.72 \times S_{tw}}{\log_{10}\left(\frac{R_w}{r}\right)}\right)} \]

Discharge (Q):

m³/s

Total Drawdown (S_tw):

Radius of Influence (R_w):

Radius of Well (r):

Coefficient of Transmissibility (T):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Coefficient of Transmissibility?

The Coefficient of Transmissibility is defined as the rate of flow of water through a vertical strip of the aquifer under unit hydraulic gradient. It represents the ability of an aquifer to transmit water through its entire saturated thickness.

2. How Does the Calculator Work?

The calculator uses the formula for confined aquifer discharge:

\[ T = \frac{Q}{\left(\frac{2.72 \times S_{tw}}{\log_{10}\left(\frac{R_w}{r}\right)}\right)} \]

Where:

\( T \) — Coefficient of Transmissibility (m²/s)
\( Q \) — Discharge rate (m³/s)
\( S_{tw} \) — Total drawdown in well (m)
\( R_w \) — Radius of influence (m)
\( r \) — Radius of well (m)

Explanation: This formula calculates the transmissibility coefficient based on pumping test data from a confined aquifer, using logarithmic relationships to account for radial flow patterns.

3. Importance of Coefficient of Transmissibility

Details: The coefficient of transmissibility is crucial for groundwater resource assessment, well design, and predicting the behavior of aquifers under pumping conditions. It helps in determining the yield potential of aquifers and designing efficient well fields.

4. Using the Calculator

Tips: Enter discharge in m³/s, drawdown in meters, and both radii in meters. All values must be positive and the radius of influence must be greater than the radius of the well for valid results.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between transmissibility and permeability?
A: Transmissibility includes the entire aquifer thickness, while permeability is a property of the material itself regardless of thickness.

Q2: What are typical values for coefficient of transmissibility?
A: Values can range from less than 10 m²/day for tight formations to over 1000 m²/day for highly productive aquifers.

Q3: When is this formula applicable?
A: This formula is specifically for confined aquifers with steady-state radial flow to a fully penetrating well.

Q4: What are the limitations of this approach?
A: The formula assumes homogeneous, isotropic aquifer conditions and may not be accurate for complex geological settings or unconfined aquifers.

Q5: How is radius of influence determined?
A: Radius of influence is typically determined from field observations during pumping tests by measuring the distance where drawdown becomes negligible.