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Unconfined Aquifer Thickness refers to the vertical extent of an unconfined aquifer measured from the water table to the underlying impermeable layer. It is a critical parameter in hydrogeology for understanding groundwater flow and storage capacity.
The calculator uses the formula:
Where:
Explanation: This formula calculates the thickness of an unconfined aquifer based on drawdown measurements from pumping tests, accounting for modified drawdown values to improve accuracy.
Details: Accurate determination of aquifer thickness is essential for groundwater resource management, well design, contaminant transport studies, and sustainable water extraction planning.
Tips: Enter drawdown in well 2 and modified drawdown 2 values in meters. Ensure s₂ > s₂' and both values are positive for valid results.
Q1: What is the difference between confined and unconfined aquifers?
A: Unconfined aquifers have a water table as their upper boundary, while confined aquifers are bounded above and below by impermeable layers.
Q2: Why is modified drawdown used in this calculation?
A: Modified drawdown accounts for additional factors like well loss or boundary effects that may affect standard drawdown measurements.
Q3: What are typical values for unconfined aquifer thickness?
A: Thickness can range from a few meters to hundreds of meters, depending on geological formations and regional hydrogeology.
Q4: When should this calculation be used?
A: This calculation is particularly useful in pumping test analysis for unconfined aquifers where modified drawdown measurements are available.
Q5: Are there limitations to this equation?
A: The formula assumes ideal conditions and may need adjustments for complex aquifer systems, well interference, or anisotropic conditions.