1. What is Total Drawdown in Pumping Well?

Total Drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test. It consists of aquifer loss and well loss components.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( s_t \) — Total Drawdown (Meter)
• \( s \) — Change in Drawdown (Meter)
• \( C \) — Well loss coefficient
• \( Q \) — Discharge rate (m³/s)
• \( n \) — Exponent (typically between 1-3)

Explanation: The equation separates total drawdown into aquifer loss (s) and well loss (CQⁿ) components, allowing for better analysis of well performance.

3. Importance of Total Drawdown Calculation

Details: Accurate calculation of total drawdown is crucial for well design, pump selection, aquifer characterization, and determining well efficiency in groundwater extraction systems.

4. Using the Calculator

Tips: Enter change in drawdown in meters, well loss coefficient, discharge rate in m³/s, and exponent value. All values must be non-negative numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for exponent n?
A: The exponent n typically ranges from 1 to 3, with n=2 commonly used for turbulent flow conditions in well systems.

Q2: How is change in drawdown different from total drawdown?
A: Change in drawdown represents aquifer loss, while total drawdown includes both aquifer loss and additional well loss due to well construction and operation.

Q3: What factors affect well loss coefficient C?
A: Well loss coefficient is influenced by well screen design, well development, formation characteristics, and pumping conditions.

Q4: When should this calculation be used?
A: This calculation is essential during aquifer tests, well performance evaluations, and when designing groundwater extraction systems.

Q5: How can well efficiency be determined from this calculation?
A: Well efficiency = (Aquifer loss / Total drawdown) × 100%. Lower well loss indicates higher well efficiency.