Discharge In Confined Aquifer With Base 10 Calculator

Discharge in Confined Aquifer Formula:

\[ Q = \frac{2.72 \times K_w \times b_w \times (H_i - h_w)}{\log_{10}\left(\frac{R_w}{r}\right)} \]

Coefficient of Permeability (K_w):

m/s

Aquifer Thickness (b_w):

Initial Aquifer Thickness (H_i):

Depth of Water (h_w):

Radius of Influence (R_w):

Radius of Well (r):

Discharge (Q):

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1. What is Discharge in Confined Aquifer?

Discharge in a confined aquifer refers to the rate of groundwater flow that can be extracted from a well in an aquifer bounded above and below by impermeable layers. It is a critical parameter in hydrogeology for water resource management and well design.

2. How Does the Calculator Work?

The calculator uses the confined aquifer discharge formula:

\[ Q = \frac{2.72 \times K_w \times b_w \times (H_i - h_w)}{\log_{10}\left(\frac{R_w}{r}\right)} \]

Where:

\( Q \) — Discharge rate (m³/s)
\( K_w \) — Coefficient of permeability (m/s)
\( b_w \) — Aquifer thickness (m)
\( H_i \) — Initial aquifer thickness (m)
\( h_w \) — Depth of water in well (m)
\( R_w \) — Radius of influence (m)
\( r \) — Radius of well (m)

Explanation: This formula calculates the steady-state discharge from a well in a confined aquifer using logarithmic approximation with base 10.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is essential for determining well yield, designing pumping systems, managing groundwater resources, and assessing the sustainability of water extraction from confined aquifers.

4. Using the Calculator

Tips: Enter all values in appropriate units (meters and meters/second). Ensure that the radius of influence is greater than the well radius, and all values are positive. The depth of water should be less than the initial aquifer thickness.

5. Frequently Asked Questions (FAQ)

Q1: What is a confined aquifer?
A: A confined aquifer is an aquifer bounded above and below by impermeable layers (aquitards or aquicludes) that restrict water movement.

Q2: Why use base 10 logarithm in this formula?
A: The base 10 logarithm is used in this particular formulation of the confined aquifer discharge equation as it provides a practical approximation for field calculations.

Q3: What is the radius of influence?
A: The radius of influence is the distance from the well center to the point where drawdown becomes negligible and the water table remains unaffected by pumping.

Q4: What are typical values for coefficient of permeability?
A: Permeability coefficients vary widely: clay (10⁻⁹ to 10⁻⁷ m/s), sand (10⁻⁵ to 10⁻³ m/s), gravel (10⁻³ to 10⁻¹ m/s).

Q5: When is this formula applicable?
A: This formula applies to steady-state flow conditions in homogeneous, isotropic confined aquifers with fully penetrating wells.