1. What is Depression Head Calculation?

The depression head calculation determines the water level depression in a well at a specific time after pumping has stopped, particularly in coarse sand aquifers. This is important for understanding aquifer recovery characteristics and groundwater flow dynamics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( h_1 \) — Initial depression head when pumping stopped (m)
• \( h_2 \) — Depression head at time T after pumping stopped (m)
• \( t \) — Time after pumping stopped (seconds)
• 2.303 — Conversion factor from natural log to base 10 log
• 3600 — Conversion factor from seconds to hours

Explanation: This formula models the recovery of water levels in wells after pumping cessation, accounting for the logarithmic nature of aquifer recovery in coarse sand formations.

3. Importance of Depression Head Calculation

Details: Accurate depression head calculation is crucial for groundwater management, well design, aquifer characterization, and determining sustainable pumping rates for water supply systems.

4. Using the Calculator

Tips: Enter the initial depression head in meters and time in seconds after pumping stopped. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is this specific to coarse sand aquifers?
A: Coarse sand aquifers have different hydraulic properties and recovery characteristics compared to fine-grained aquifers, requiring specific calculation methods.

Q2: What time units should be used?
A: Time should be entered in seconds, as the formula includes conversion to hours internally.

Q3: How accurate is this calculation?
A: The calculation provides a theoretical estimate based on ideal conditions. Actual field conditions may vary due to aquifer heterogeneity and other factors.

Q4: When is this calculation most applicable?
A: This calculation is most applicable for homogeneous coarse sand aquifers with well-defined recovery patterns after pumping cessation.

Q5: What are typical depression head values?
A: Depression head values vary widely depending on aquifer properties, pumping rates, and duration, typically ranging from 0.1 to 10 meters in most applications.