1. What is Specific Capacity?

Specific Capacity is the quantity that which a water well can produce per unit of drawdown. It is a key parameter in hydrogeology for evaluating well performance and aquifer characteristics.

2. How Does the Calculator Work?

The calculator uses the Specific Capacity formula:

Where:

• \( Sc \) — Specific Capacity (m²/s)
• \( Q \) — Discharge rate (m³/s)
• \( st \) — Total Drawdown in Well (m)

Explanation: The formula calculates the well's productivity by dividing the discharge rate by the total drawdown observed during pumping.

3. Importance of Specific Capacity Calculation

Details: Specific Capacity is crucial for well design, determining optimal pumping rates, assessing aquifer productivity, and monitoring well performance over time.

4. Using the Calculator

Tips: Enter discharge in m³/s and total drawdown in meters. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a good Specific Capacity value?
A: Higher Specific Capacity values indicate better well performance. Values vary by aquifer type, but generally values above 0.1 m²/s are considered good.

Q2: How does Specific Capacity relate to transmissivity?
A: Specific Capacity is proportional to transmissivity. Higher Specific Capacity typically indicates higher aquifer transmissivity.

Q3: Why might Specific Capacity decrease over time?
A: Decreases can indicate well screen clogging, aquifer depletion, or other changes in well or aquifer conditions that require investigation.

Q4: When should Specific Capacity tests be conducted?
A: During well development, after rehabilitation, and periodically during well operation to monitor performance changes.

Q5: Are there limitations to this calculation?
A: The calculation assumes steady-state conditions and may not account for partial penetration effects, well efficiency, or non-linear drawdown behavior.