Drawdown Given Well Function Calculator

Drawdown Given Well Function Formula:

\[ s_t = \frac{Q \times W_u}{4 \times \pi \times F_c} \]

Total Drawdown in Well (s_t):

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1. What is the Drawdown Given Well Function Formula?

The Drawdown Given Well Function formula calculates the total drawdown in a well using discharge, well function, and formation constant parameters. This formula is essential in hydrogeology for analyzing aquifer characteristics and well performance during pumping tests.

2. How Does the Calculator Work?

The calculator uses the drawdown formula:

\[ s_t = \frac{Q \times W_u}{4 \times \pi \times F_c} \]

Where:

\( s_t \) — Total Drawdown in Well (m)
\( Q \) — Discharge (m³/s)
\( W_u \) — Well Function of u (dimensionless)
\( F_c \) — Formation Constant for Unsteady Flow (m²/s)
\( \pi \) — Archimedes' constant (approximately 3.1416)

Explanation: The formula relates the drawdown in a well to the pumping rate, well function value, and formation constant, providing insights into aquifer properties.

3. Importance of Total Drawdown Calculation

Details: Accurate drawdown calculation is crucial for determining aquifer characteristics, well efficiency, and sustainable pumping rates in groundwater resource management.

4. Using the Calculator

Tips: Enter discharge in m³/s, well function value (dimensionless), and formation constant in m²/s. All values must be positive and valid for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What is the Well Function of u?
A: Well Function of u is a dimensionless parameter derived from the Theis equation that represents the relationship between drawdown and time in an aquifer.

Q2: How is Formation Constant determined?
A: Formation Constant is typically determined through aquifer pumping tests and represents the transmissivity and storage properties of the aquifer.

Q3: What are typical values for Well Function?
A: Well Function values typically range from 0.1 to 10, depending on the time since pumping began and aquifer characteristics.

Q4: When is this formula most applicable?
A: This formula is most applicable for confined aquifers under unsteady flow conditions during pumping tests.

Q5: What units should be used for input values?
A: Discharge should be in m³/s, Well Function is dimensionless, and Formation Constant should be in m²/s for consistent results.