Thickness Of Aquifer For Discharge In Unconfined Aquifer With Base 10 Calculator

Formula Used:

\[ b = \sqrt{h_w^2 + \frac{Q \cdot \log_{10}\left(\frac{R_w}{r}\right)}{1.36 \cdot K_s}} \]

Depth of Water (hw):

Discharge (Q):

m³/s

Radius of Influence (Rw):

Radius of well (r):

Standard Coefficient of Permeability at 20°C (Ks):

Thickness of Aquifer (b):

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1. What is the Thickness of Aquifer Formula?

The Thickness of Aquifer formula calculates the vertical thickness of a hydrogeologically defined aquifer where pore spaces are saturated with water. This formula is specifically designed for unconfined aquifers using base 10 logarithms.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ b = \sqrt{h_w^2 + \frac{Q \cdot \log_{10}\left(\frac{R_w}{r}\right)}{1.36 \cdot K_s}} \]

Where:

\( b \) — Thickness of Aquifer (m)
\( h_w \) — Depth of Water in the well measured above the impermeable layer (m)
\( Q \) — Discharge rate (m³/s)
\( R_w \) — Radius of Influence measured from center of well to where drawdown curve meets original water table (m)
\( r \) — Radius of well (m)
\( K_s \) — Standard Coefficient of Permeability at 20°C

Explanation: The equation calculates aquifer thickness by considering water depth, discharge rate, well geometry, and soil permeability characteristics.

3. Importance of Aquifer Thickness Calculation

Details: Accurate aquifer thickness estimation is crucial for groundwater resource assessment, well design, pumping test analysis, and sustainable water management in unconfined aquifer systems.

4. Using the Calculator

Tips: Enter all values in appropriate units (meters for lengths, m³/s for discharge). Ensure all values are positive and radius of influence is greater than well radius for valid results.

5. Frequently Asked Questions (FAQ)

Q1: What is an unconfined aquifer?
A: An unconfined aquifer has a water table that serves as its upper boundary and is open to atmospheric pressure.

Q2: Why use base 10 logarithm in this formula?
A: Base 10 logarithms are commonly used in hydrogeological calculations as they provide convenient scaling for the large range of values typically encountered.

Q3: What is the significance of the 1.36 coefficient?
A: The 1.36 coefficient is derived from empirical relationships and unit conversions that make the formula dimensionally consistent.

Q4: How does permeability affect aquifer thickness?
A: Higher permeability typically results in greater calculated aquifer thickness as water can flow more easily through the porous medium.

Q5: When is this formula most applicable?
A: This formula is most applicable for steady-state flow conditions in homogeneous, isotropic unconfined aquifers with fully penetrating wells.