Question Bank • QB_IDE_GWH_004 NAT • 2 Marks

Section 5: Irrigation and Drainage Engineering

Groundwater Hydrology

Subtopic: Steady and unsteady flow in confined and unconfined aquifers

Question Statement:

In an unsteady pumping test in a confined aquifer, drawdown is plotted against time on semi-logarithmic paper (Cooper-Jacob method). The drawdown per log cycle of time is $\Delta s = 1.20\text{ m}$. The constant pumping discharge is $Q = 3456\text{ m}^3\text{/day}$ ($= 0.040\text{ m}^3\text{/s}$). Using Cooper-Jacob's relation $T = \frac{2.303 Q}{4 \pi \Delta s}$, the aquifer transmissivity $T$ in $\text{m}^2\text{/day}$ is ________ (round off to 1 decimal place). Take $\pi = 3.1416$.

Answer Key:

527.8

Step-by-Step Solution & Explanation

From Cooper-Jacob's approximation: $T = \frac{2.303 \cdot Q}{4 \pi \Delta s}$ Given: • $Q = 3456\text{ m}^3\text{/day}$ • $\Delta s = 1.20\text{ m}$ • $\pi = 3.1416$ $T = \frac{2.303 \times 3456}{4 \times 3.1416 \times 1.20} = \frac{7959.168}{15.07968} \approx 527.81\text{ m}^2\text{/day} \approx 527.8\text{ m}^2\text{/day}$
← Previous (QB_IDE_ADV_100) Next (QB_IDE_EXP_034) →

Practice In Authentic CBT Exam Interface

Test your skills under authentic timed conditions with live scoring and AIR percentile ranking.

Launch CBT Mock Test