Aquifer Constant Calculator

Aquifer Constant Formula:

\[ T = \frac{Q \cdot \log_{10}(r_2/r_1)}{2.72 \cdot (s_1 - s_2)} \]

Discharge (Q):

m³/s

Radial Distance at Observation Well 1 (r₁):

Radial Distance at Observation Well 2 (r₂):

Drawdown in Well 1 (s₁):

Drawdown in Well 2 (s₂):

Aquifer Constant (T):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Aquifer Constant?

The Aquifer Constant, also known as coefficient of transmissibility, represents the rate at which water is transmitted through a unit width of aquifer under a unit hydraulic gradient. It is a key parameter in groundwater hydrology for characterizing aquifer properties.

2. How Does the Calculator Work?

The calculator uses the aquifer constant formula:

\[ T = \frac{Q \cdot \log_{10}(r_2/r_1)}{2.72 \cdot (s_1 - s_2)} \]

Where:

\( T \) — Aquifer Constant/Transmissibility (m²/s)
\( Q \) — Discharge rate (m³/s)
\( r_1 \) — Radial distance at observation well 1 (m)
\( r_2 \) — Radial distance at observation well 2 (m)
\( s_1 \) — Drawdown in well 1 (m)
\( s_2 \) — Drawdown in well 2 (m)

Explanation: This formula calculates the transmissibility of an aquifer based on pumping test data from two observation wells.

3. Importance of Aquifer Constant Calculation

Details: Accurate calculation of aquifer constant is crucial for groundwater resource assessment, well field design, contaminant transport modeling, and sustainable groundwater management.

4. Using the Calculator

Tips: Enter discharge in m³/s, radial distances in meters, and drawdown values in meters. All values must be positive, and drawdown values must be different (s₁ ≠ s₂).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of aquifer constant values?
A: Aquifer constant values typically range from 0.001 to 0.1 m²/s for most aquifers, with higher values indicating more transmissive aquifers.

Q2: Why use logarithmic function in the formula?
A: The logarithmic function accounts for the radial flow pattern around pumping wells, which follows logarithmic distribution of drawdown.

Q3: What are the limitations of this calculation method?
A: This method assumes homogeneous, isotropic aquifer conditions, steady-state flow, and fully penetrating wells. Real-world conditions may vary.

Q4: How does aquifer constant relate to hydraulic conductivity?
A: Aquifer constant (T) equals hydraulic conductivity (K) multiplied by aquifer thickness (b): T = K × b.

Q5: When should this calculation be used?
A: This calculation is primarily used for analyzing pumping test data from multiple observation wells to determine aquifer transmissibility.