Discharge Given Drawdown Calculator

Discharge Formula:

\[ Q = \frac{4\pi F_c s_t}{W(u)} \]

Discharge (Q):

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1. What is the Discharge Given Drawdown Formula?

The Discharge Given Drawdown formula calculates the rate of flow of a fluid in unsteady flow conditions, specifically in hydrogeology for aquifer testing. It relates discharge to formation constant, total drawdown, and the well function.

2. How Does the Calculator Work?

The calculator uses the discharge formula:

\[ Q = \frac{4\pi F_c s_t}{W(u)} \]

Where:

\( Q \) — Discharge (m³/s)
\( \pi \) — Archimedes' constant (approximately 3.14159)
\( F_c \) — Formation constant for unsteady flow (m²/s)
\( s_t \) — Total drawdown in well (m)
\( W(u) \) — Well function of u (dimensionless)

Explanation: This formula calculates the discharge rate based on aquifer properties and observed drawdown measurements during pumping tests.

3. Importance of Discharge Calculation

Details: Accurate discharge calculation is essential for determining aquifer characteristics, designing well systems, and managing groundwater resources effectively.

4. Using the Calculator

Tips: Enter formation constant in m²/s, total drawdown in meters, and well function value. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the formation constant (Fc)?
A: The formation constant represents the hydraulic conductivity and storage properties of an aquifer, typically determined through aquifer tests.

Q2: How is total drawdown measured?
A: Total drawdown is the difference between the static water level and the pumping water level, measured in meters at the well.

Q3: What is the well function W(u)?
A: The well function is a dimensionless parameter that represents the theoretical drawdown in a confined aquifer, dependent on the time and distance from the pumping well.

Q4: When is this formula applicable?
A: This formula is used for analyzing unsteady flow in confined aquifers during pumping tests and is based on the Theis solution.

Q5: What are typical units for discharge?
A: Discharge is typically measured in cubic meters per second (m³/s), but may also be expressed in liters per second or gallons per minute depending on the application.