Transmissivity Given Discharge Quantity Calculator

Transmissivity Formula:

\[ \tau = \frac{V_w}{b} \times \frac{dl}{\Delta H} \]

Total Water Volume (Vw):

m³/s

Aquifer Thickness (b):

Distance Between Points (dl):

Change in Head (ΔH):

Transmissivity (τ):

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1. What is Transmissivity?

Transmissivity refers to the measure of how much water can be transmitted horizontally through an aquifer. It is the product of the hydraulic conductivity of the aquifer and its saturated thickness, providing a key parameter for groundwater flow analysis.

2. How Does the Calculator Work?

The calculator uses the transmissivity formula:

\[ \tau = \frac{V_w}{b} \times \frac{dl}{\Delta H} \]

Where:

\( \tau \) — Transmissivity (m²/s)
\( V_w \) — Total water volume (m³/s)
\( b \) — Aquifer thickness (m)
\( dl \) — Distance between points (m)
\( \Delta H \) — Change in head between points (m)

Explanation: The equation calculates the transmissivity by considering the water volume, aquifer characteristics, and hydraulic gradient between two measurement points.

3. Importance of Transmissivity Calculation

Details: Accurate transmissivity calculation is crucial for groundwater resource management, well field design, contaminant transport modeling, and predicting aquifer response to pumping.

4. Using the Calculator

Tips: Enter total water volume in m³/s, aquifer thickness in meters, distance between points in meters, and change in head in meters. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of transmissivity values?
A: Transmissivity values can range from less than 1 m²/day for tight formations to over 1000 m²/day for highly productive aquifers.

Q2: How does transmissivity differ from hydraulic conductivity?
A: Hydraulic conductivity is a property of the porous material alone, while transmissivity incorporates both the material properties and the aquifer thickness.

Q3: When is this formula most applicable?
A: This formula is particularly useful for calculating transmissivity from pumping test data or when discharge quantities and hydraulic gradients are known.

Q4: What are the limitations of this calculation method?
A: The method assumes homogeneous aquifer conditions and may not accurately represent complex geological settings with varying hydraulic properties.

Q5: How does temperature affect transmissivity calculations?
A: Temperature affects water viscosity, which influences hydraulic conductivity. For precise calculations, temperature corrections may be necessary.