Confined Aquifer Discharge Given Aquifer Constant Calculator

Formula Used:

\[ Q = \frac{T}{\frac{\log\left(\frac{r_2}{r_1},10\right)}{2.72 \times (s_1 - s_2)}} \]

Aquifer Constant (T):

m²/day

Radial Distance at Observation Well 2 (r₂):

Radial Distance at Observation Well 1 (r₁):

Drawdown in Well 1 (s₁):

Drawdown in Well 2 (s₂):

Discharge (Q):

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1. What Is The Confined Aquifer Discharge Formula?

The confined aquifer discharge formula calculates the rate of groundwater flow in a confined aquifer system using the aquifer constant, radial distances from observation wells, and drawdown measurements. This is essential for groundwater resource management and well field design.

2. How Does The Calculator Work?

The calculator uses the formula:

\[ Q = \frac{T}{\frac{\log\left(\frac{r_2}{r_1},10\right)}{2.72 \times (s_1 - s_2)}} \]

Where:

\( Q \) — Discharge (m³/s)
\( T \) — Aquifer Constant/Transmissivity (m²/day)
\( r_2 \) — Radial Distance at Observation Well 2 (m)
\( r_1 \) — Radial Distance at Observation Well 1 (m)
\( s_1 \) — Drawdown in Well 1 (m)
\( s_2 \) — Drawdown in Well 2 (m)

Explanation: The formula calculates groundwater discharge by considering the logarithmic relationship between radial distances and the difference in drawdown measurements between two observation wells.

3. Importance Of Discharge Calculation

Details: Accurate discharge calculation is crucial for sustainable groundwater management, determining well yields, designing pumping systems, and assessing the impact of extraction on aquifer systems.

4. Using The Calculator

Tips: Enter all values in appropriate units. Ensure radial distances and drawdown values are positive numbers, and that the difference between drawdown measurements is not zero for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is aquifer transmissivity?
A: Aquifer transmissivity (T) is the rate at which water is transmitted through a unit width of aquifer under a unit hydraulic gradient, typically measured in m²/day.

Q2: Why use logarithmic function in the formula?
A: The logarithmic function accounts for the radial flow pattern in confined aquifers, where flow decreases logarithmically with distance from the pumping well.

Q3: What are typical values for aquifer transmissivity?
A: Transmissivity values vary widely from less than 10 m²/day for low-permeability aquifers to over 1000 m²/day for highly productive aquifers.

Q4: When is this formula applicable?
A: This formula applies to confined aquifers with steady-state flow conditions and fully penetrating wells in homogeneous, isotropic aquifers.

Q5: What are the limitations of this approach?
A: The formula assumes ideal conditions and may not accurately represent complex aquifer systems with heterogeneity, boundary effects, or time-varying conditions.