Discharge In Confined Aquifer Given Coefficient Of Transmissibility Calculator

Formula Used:

\[ Discharge = \frac{2\pi \times Coefficient\ of\ Transmissibility \times (Initial\ Aquifer\ Thickness - Depth\ of\ Water)}{\ln\left(\frac{Radius\ of\ Influence}{Radius\ of\ well}\right)} \]

Coefficient of Transmissibility:

m²/s

Initial Aquifer Thickness:

Depth of Water:

Radius of Influence:

Radius of Well:

Discharge:

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1. What is the Discharge in Confined Aquifer Formula?

The discharge formula for confined aquifers calculates the rate of groundwater flow using the coefficient of transmissibility, aquifer thickness, water depth, and geometric properties of the well system. This equation is fundamental in hydrogeology for determining well yield and aquifer characteristics.

2. How Does the Calculator Work?

The calculator uses the discharge formula:

\[ Q = \frac{2\pi T (H_i - h_w)}{\ln\left(\frac{R}{r}\right)} \]

Where:

\( Q \) — Discharge (m³/s)
\( T \) — Coefficient of Transmissibility (m²/s)
\( H_i \) — Initial Aquifer Thickness (m)
\( h_w \) — Depth of Water in well (m)
\( R \) — Radius of Influence (m)
\( r \) — Radius of Well (m)
\( \pi \) — Archimedes' constant (3.14159)
\( \ln \) — Natural logarithm function

Explanation: The formula calculates groundwater discharge based on the transmissibility of the aquifer and the geometric configuration of the well system.

3. Importance of Discharge Calculation

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

4. Using the Calculator

Tips: Enter all values in appropriate units. Ensure the radius of influence is greater than the radius of the well. All values must be positive, and the initial aquifer thickness should be greater than the depth of water.

5. Frequently Asked Questions (FAQ)

Q1: What is the coefficient of transmissibility?
A: The coefficient of transmissibility represents the rate at which water is transmitted through a unit width of aquifer under a 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: What's the difference between confined and unconfined aquifers?
A: Confined aquifers are bounded above and below by impermeable layers, while unconfined aquifers have a water table that serves as the upper boundary.

Q4: When is this formula applicable?
A: This formula applies to steady-state flow in homogeneous, isotropic confined aquifers with fully penetrating wells.

Q5: What are typical values for coefficient of transmissibility?
A: Values range from 0.1 m²/day for fine-grained aquifers to over 1000 m²/day for highly productive coarse-grained aquifers.