Radius Of Influence Given Confined Aquifer Discharge Calculator

Radius of Influence Formula:

\[ \text{Radius of Influence} = \text{Radius of well} \times \exp\left(\frac{2\pi \times \text{Coefficient of Permeability} \times \text{Aquifer Thickness} \times \text{Total Drawdown}}{\text{Discharge}}\right) \]

Radius of Well (r):

Coefficient of Permeability (KWH):

m/s

Aquifer Thickness During Pumping (bp):

Total Drawdown in Well (st):

Discharge of Liquid (Qli):

m³/s

Radius of Influence (Rw):

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1. What is Radius of Influence?

The Radius of Influence is measured from the center of the well to the point where the drawdown curve meets the original water table. It represents the extent of the cone of depression created by pumping from a well.

2. How Does the Calculator Work?

The calculator uses the Radius of Influence formula:

Where:

Radius of well (r) - Distance from center of well to its outer boundary (m)
Coefficient of Permeability (KWH) - Describes how easily liquid moves through soil (m/s)
Aquifer Thickness During Pumping (bp) - Thickness of aquifer during pumping stage (m)
Total Drawdown in Well (st) - Reduction in hydraulic head observed at a well (m)
Discharge of Liquid (Qli) - Rate of flow of liquid (m³/s)
π - Archimedes' constant (approximately 3.1416)
exp - Exponential function

3. Importance of Radius of Influence Calculation

Details: Calculating the radius of influence is crucial for well field design, determining well spacing, assessing interference between wells, and managing groundwater resources effectively.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure all values are positive and valid for accurate results. The calculator provides the radius of influence in meters.

5. Frequently Asked Questions (FAQ)

Q1: What factors affect the radius of influence?
A: The radius of influence is affected by aquifer properties (permeability, thickness), pumping rate, duration of pumping, and the well's characteristics.

Q2: How does permeability affect the radius of influence?
A: Higher permeability generally results in a larger radius of influence as water can move more easily through the aquifer material.

Q3: What is the typical range for radius of influence?
A: The radius of influence can range from a few meters to several kilometers, depending on aquifer conditions and pumping rates.

Q4: How does pumping rate affect the radius of influence?
A: Higher pumping rates typically create a larger cone of depression and thus a larger radius of influence.

Q5: Can this formula be used for unconfined aquifers?
A: This specific formula is designed for confined aquifers. Different equations are used for unconfined aquifers due to different hydraulic conditions.