Subtopic: Steady and unsteady flow in confined and unconfined aquifers
Question Statement:
A fully penetrating well of diameter $30\text{ cm}$ penetrates a confined aquifer of thickness $15\text{ m}$ and hydraulic conductivity $25\text{ m/day}$. When pumped at steady state, the radius of influence is $300\text{ m}$ and the drawdown in the well is $4.0\text{ m}$. The steady discharge of the well is ________ $\text{m}^3/\text{day}$ (round off to 1 decimal place).
Answer Key:
1240
Step-by-Step Solution & Explanation
Thiem's Well Formula:
$Q = \frac{2\pi K b s_w}{\ln(R / r_w)} = \frac{2\pi \times 25 \times 15 \times 4.0}{\ln(300 / 0.15)} = \frac{9424.78}{\ln(2000)} = \frac{9424.78}{7.6009} \approx 1239.95\text{ m}^3/\text{day}$
Rounding to 1 decimal place: **1240.0** $\text{m}^3/\text{day}$.