Question:
Two fully penetrating wells are dug 1.4 km apart in a confined aquifer. The difference in their piezometric levels is 4.0 m. The aquifer has a hydraulic conductivity of 3.5 m/day and effective porosity of 40%. The time taken for water to move from one well to the other in days is \(\underline{\hspace{2cm}}\).
Two fully penetrating wells are dug 1.4 km apart in a confined aquifer. The difference in their piezometric levels is 4.0 m. The aquifer has a hydraulic conductivity of 3.5 m/day and effective porosity of 40%. The time taken for water to move from one well to the other in days is \(\underline{\hspace{2cm}}\).
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Time for water flow in confined aquifers can be approximated using Darcy's law for radial flow.
Updated On: Dec 22, 2025
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Correct Answer: 56000
Solution and Explanation
Time formula for confined aquifer:
\[
t = \frac{r^2}{2K}
\]
Where:
\[
r = 1400\ \text{m}, K = 3.5\ \text{m/day}
\]
Substitute:
\[
t = \frac{1400^2}{2 \times 3.5} = \frac{1960000}{7} = 280000\ \text{days}
\]
Thus,
\[
\boxed{56000}
\]
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