1. What is the Difference in Drawdowns Formula?

The formula calculates the difference in drawdowns at two wells based on discharge rate and aquifer constant (coefficient of transmissibility). It's used in hydrogeology to analyze groundwater flow characteristics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Delta s \) — Difference in drawdowns at the two wells (m)
• \( Q \) — Discharge rate (m³/s)
• \( T \) — Aquifer constant/coefficient of transmissibility

Explanation: The formula relates the difference in water level drawdown between two observation wells to the pumping rate and the aquifer's transmissivity properties.

3. Importance of Drawdown Calculation

Details: Accurate drawdown calculations are crucial for groundwater resource management, well field design, and understanding aquifer characteristics for sustainable water extraction.

4. Using the Calculator

Tips: Enter discharge in cubic meters per second and aquifer constant value. Both values must be positive numbers greater than zero for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is aquifer constant/transmissibility?
A: Aquifer constant (T) represents the rate at which water is transmitted through a unit width of aquifer under a unit hydraulic gradient.

Q2: Why is the constant 2.72 used in the formula?
A: The constant 2.72 is derived from natural logarithmic relationships in groundwater flow equations and represents the base of natural logarithms (e).

Q3: What are typical units for these measurements?
A: Discharge is typically in m³/s, aquifer constant in m²/day, and drawdown difference in meters.

Q4: When is this formula most applicable?
A: This formula is most applicable for confined aquifers with steady-state flow conditions and homogeneous aquifer properties.

Q5: What factors can affect drawdown measurements?
A: Aquifer heterogeneity, boundary conditions, pumping duration, and well construction can all affect actual drawdown measurements.