Discharge Through Each Well When Interference Among Well Is Present Calculator

Formula Used:

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

Coefficient of Permeability (K):

m/s

Aquifer Thickness During Pumping (b_p):

Aquifer Thickness (b_w):

Depth of Water (h_w):

Radius of Influence (R):

Radius of Well (r'):

Distance Between Well (B):

Discharge (Q):

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1. What is Discharge Through Each Well When Interference Among Well Is Present?

This calculation determines the discharge rate from each well when multiple wells are operating simultaneously and interfering with each other's drawdown patterns. It accounts for the complex hydraulic interactions between closely spaced wells in an aquifer system.

2. How Does the Calculator Work?

The calculator uses the formula:

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

Where:

\( Q \) — Discharge from each well (m³/s)
\( K \) — Coefficient of permeability (m/s)
\( b_p \) — Aquifer thickness during pumping (m)
\( b_w \) — Aquifer thickness (m)
\( h_w \) — Depth of water in the well (m)
\( R \) — Radius of influence (m)
\( r' \) — Radius of well (m)
\( B \) — Distance between wells (m)
\( \pi \) — Mathematical constant pi (≈3.1416)
\( \ln \) — Natural logarithm function

Explanation: The formula accounts for the interference effects between multiple wells by incorporating the distance between wells and their respective influence radii in the logarithmic term of the denominator.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is crucial for designing well fields, optimizing pumping rates, preventing over-extraction, and maintaining sustainable groundwater management practices when multiple wells operate simultaneously.

4. Using the Calculator

Tips: Enter all parameters in consistent units (meters and meters/second). Ensure that aquifer thickness values are positive and that the radius of influence is greater than the well radius and distance between wells for meaningful results.

5. Frequently Asked Questions (FAQ)

Q1: What is well interference?
A: Well interference occurs when multiple wells are pumping from the same aquifer, causing their individual drawdown cones to overlap and affect each other's performance.

Q2: How does distance between wells affect discharge?
A: Closer well spacing typically reduces individual well discharge due to increased interference, while greater distances allow wells to operate more independently.

Q3: What is the radius of influence?
A: The distance from the well center to the point where the drawdown curve meets the original water table, representing the extent of the well's impact on the aquifer.

Q4: When is this calculation most applicable?
A: This calculation is particularly important for well field design in confined or unconfined aquifers where multiple extraction wells operate simultaneously.

Q5: What are the limitations of this formula?
A: The formula assumes homogeneous aquifer properties, steady-state conditions, and may not account for complex geological formations or transient pumping conditions.