Thickness Of Aquifer From Impermeable Layer When Interference Among Well Is Present Calculator

Formula Used:

\[ H_i = h_w + \frac{Q \cdot \ln\left(\frac{R^2}{r' \cdot B}\right)}{2\pi K b_w} \]

Depth of Water (h_w):

Discharge (Q):

m³/s

Radius of Influence (R):

Radius of Well (r'):

Distance Between Well (B):

Coefficient of Permeability (K):

m/s

Aquifer Thickness (b_w):

Initial Aquifer Thickness (H_i):

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1. What is the Aquifer Thickness Formula?

The formula calculates the initial aquifer thickness from an impermeable layer when interference among wells is present. It accounts for various hydrogeological parameters including discharge, permeability, and geometric relationships between wells.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ H_i = h_w + \frac{Q \cdot \ln\left(\frac{R^2}{r' \cdot B}\right)}{2\pi K b_w} \]

Where:

\( H_i \) — Initial Aquifer Thickness (m)
\( h_w \) — Depth of Water in the well (m)
\( Q \) — Discharge rate (m³/s)
\( R \) — Radius of Influence (m)
\( r' \) — Radius of Well (m)
\( B \) — Distance Between Wells (m)
\( K \) — Coefficient of Permeability (m/s)
\( b_w \) — Aquifer Thickness (m)
\( \pi \) — Archimedes' constant (≈3.1416)
\( e \) — Napier's constant (≈2.7183)

Explanation: The formula calculates the initial aquifer thickness by considering the hydraulic properties of the aquifer system and the interference effects between multiple wells.

3. Importance of Aquifer Thickness Calculation

Details: Accurate calculation of aquifer thickness is crucial for groundwater resource assessment, well design, pumping test analysis, and understanding the sustainable yield of aquifer systems.

4. Using the Calculator

Tips: Enter all parameters in consistent units (meters and m³/s). Ensure all values are positive and valid. The calculator uses natural logarithm (base e) for the calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of well interference?
A: Well interference occurs when multiple wells extract water from the same aquifer, causing overlapping drawdown cones that affect each well's performance and the overall aquifer response.

Q2: How does distance between wells affect the calculation?
A: Closer well spacing increases interference effects, leading to greater drawdown and potentially reduced well yields compared to isolated wells.

Q3: What is the radius of influence?
A: The distance from a well center to the point where drawdown becomes negligible, typically where the drawdown curve meets the original water table.

Q4: When is this formula most applicable?
A: This formula is particularly useful for confined aquifers or unconfined aquifers with small drawdown relative to aquifer thickness, where multiple wells are operating simultaneously.

Q5: What are the limitations of this approach?
A: The formula assumes homogeneous, isotropic aquifer conditions and may not accurately represent complex geological settings or transient pumping conditions.