1. What is the Drawdown Calculation?

The drawdown calculation determines the possible drawdown in a confined aquifer by subtracting the measured drawdown from the initial constant piezometric head. This provides insight into groundwater behavior and aquifer characteristics under pumping conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Possible Drawdown in Confined Aquifer} \) — The drawdown that would have occurred if the aquifer had been confined
• \( \text{Initial Constant Piezometric Head} \) — The initial pressure head in a groundwater system
• \( \text{Drawdown} \) — The difference in height between the natural water table and the water level in a well after extraction

Explanation: This calculation helps determine the theoretical maximum drawdown that would occur in a perfectly confined aquifer system.

3. Importance of Drawdown Calculation

Details: Accurate drawdown calculation is crucial for groundwater resource management, well design, pumping test analysis, and understanding aquifer response to extraction.

4. Using the Calculator

Tips: Enter the initial constant piezometric head and measured drawdown values in meters. Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is piezometric head?
A: Piezometric head is the hydraulic head in a confined aquifer, representing the pressure potential at a specific point in the groundwater system.

Q2: How does confined aquifer differ from unconfined?
A: A confined aquifer is bounded above and below by impermeable layers, while an unconfined aquifer has a water table that serves as its upper boundary.

Q3: Why calculate possible drawdown?
A: Calculating possible drawdown helps engineers and hydrologists understand aquifer performance and predict water level changes during pumping.

Q4: What factors affect drawdown?
A: Drawdown is affected by pumping rate, aquifer properties, well construction, and duration of pumping.

Q5: How accurate is this calculation?
A: The calculation provides a theoretical value; actual field conditions may vary due to aquifer heterogeneity and other geological factors.