Equation For Drawdown Across One Log Cycle Calculator

Equation For Drawdown Across One Log Cycle:

\[ \Delta s_D = \frac{2.3 \times q}{\tau \times 4 \times \pi} \]

Drawdown Across Log Cycle (ΔsD):

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1. What is the Equation For Drawdown Across One Log Cycle?

The Equation For Drawdown Across One Log Cycle estimates the change in water level (or hydraulic head) in an aquifer due to pumping from a well across one logarithmic cycle of time. This equation is fundamental in hydrogeology for analyzing aquifer test data and determining aquifer properties.

2. How Does the Calculator Work?

The calculator uses the equation:

\[ \Delta s_D = \frac{2.3 \times q}{\tau \times 4 \times \pi} \]

Where:

\( \Delta s_D \) — Drawdown across log cycle (m)
\( q \) — Pumping rate (m³/s)
\( \tau \) — Transmissivity (m²/s)
\( \pi \) — Archimedes' constant (approximately 3.1416)

Explanation: This equation calculates the drawdown that occurs across one logarithmic cycle of time during a pumping test, which is used to determine the transmissivity of an aquifer.

3. Importance of Drawdown Calculation

Details: Accurate drawdown calculation is crucial for determining aquifer properties, designing well fields, managing groundwater resources, and predicting the impacts of pumping on groundwater levels.

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 for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is drawdown in hydrogeology?
A: Drawdown refers to the lowering of the water table or potentiometric surface caused by pumping from a well.

Q2: Why is the logarithmic cycle important?
A: The logarithmic cycle allows for the analysis of time-drawdown data to determine aquifer properties using semi-log plots.

Q3: What is transmissivity?
A: Transmissivity is the rate at which water is transmitted through a unit width of an aquifer under a unit hydraulic gradient.

Q4: When is this equation typically used?
A: This equation is used during pumping tests to analyze time-drawdown data and determine the transmissivity of confined aquifers.

Q5: Are there limitations to this equation?
A: This approach assumes ideal conditions (homogeneous isotropic aquifer, fully penetrating well, constant pumping rate) and may need adjustments for real-world complexities.