Confined Aquifer Discharge with Base 10 given Coefficient of Transmissibility Calculator

Formula Used:

\[ Q = \frac{2.72 \times T \times s}{\log_{10}\left(\frac{R}{r}\right)} \]

Coefficient of Transmissibility (T):

m²/s

Total Drawdown (s):

Radius of Influence (R):

Radius of Well (r):

Discharge (Q):

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1. What is the Confined Aquifer Discharge Formula?

The confined aquifer discharge formula calculates the rate of groundwater flow from a well in a confined aquifer. It uses the coefficient of transmissibility, drawdown, and geometric parameters to estimate the discharge rate.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = \frac{2.72 \times T \times s}{\log_{10}\left(\frac{R}{r}\right)} \]

Where:

\( Q \) — Discharge rate (m³/s)
\( T \) — Coefficient of transmissibility (m²/s)
\( s \) — Total drawdown (m)
\( R \) — Radius of influence (m)
\( r \) — Radius of well (m)

Explanation: The formula calculates groundwater discharge based on aquifer properties and well geometry, using logarithmic scaling for the radial flow pattern.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is crucial for well design, groundwater resource management, and determining sustainable pumping rates for confined aquifers.

4. Using the Calculator

Tips: Enter all values in consistent units (meters and m²/s). Ensure radius of influence is greater than well radius. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is coefficient of transmissibility?
A: The coefficient of transmissibility represents the rate of water flow through a vertical strip of aquifer under unit hydraulic gradient.

Q2: How is radius of influence determined?
A: Radius of influence is typically determined through pumping tests and represents the distance from the well where drawdown becomes negligible.

Q3: When is this formula applicable?
A: This formula applies to confined aquifers with steady-state flow conditions and fully penetrating wells.

Q4: What are the limitations of this formula?
A: The formula assumes homogeneous isotropic aquifer, constant pumping rate, and negligible well storage effects.

Q5: How accurate is this calculation?
A: Accuracy depends on the precision of input parameters. Field measurements and pumping tests provide the most reliable input values.