1. What is Drawdown Across One Log Cycle?

The Drawdown Across One Log Cycle refers to the change in water level (or hydraulic head) in an aquifer due to pumping from a well over one logarithmic cycle of time.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Delta s \) — Drawdown across one log cycle (m)
• \( q \) — Pumping rate (m³/s)
• \( T \) — Transmissivity (m²/s)

Explanation: This formula calculates the drawdown across one logarithmic cycle based on the pumping rate and aquifer transmissivity.

3. Importance of Drawdown Calculation

Details: Accurate drawdown calculation is crucial for well design, aquifer testing, and understanding the response of an aquifer to pumping stresses.

4. Using the Calculator

Tips: Enter pumping rate in m³/s and transmissivity in m²/s. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is transmissivity?
A: Transmissivity is the rate at which groundwater flows horizontally through an aquifer, measured in m²/s.

Q2: Why is the constant 70 used in the formula?
A: The constant 70 is derived from the Theis equation and represents the conversion factor for one logarithmic cycle.

Q3: What are typical transmissivity values?
A: Transmissivity values vary widely depending on aquifer material, ranging from 0.001 m²/s for clay to over 0.1 m²/s for highly permeable sand and gravel aquifers.

Q4: When is this formula most applicable?
A: This formula is particularly useful for analyzing pumping test data and determining aquifer properties from time-drawdown data.

Q5: Are there limitations to this approach?
A: This method assumes ideal aquifer conditions and may need modification for complex geological settings or boundary conditions.