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Two observation wells penetrated into a confined acquifer and located 1.5 km apart in the direction of flow, indicate head of 45 m and 20m. If the coefficient of permeability of the acquifer is 30m/day and porosity is 0.25, the time of travel of an inert tracer from one well to another is
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- 416.7 days
- 500 days
- 750 days
- 3000 days
Correct Option: C
Discharge velocity,
V = hydraulic gradient (i) × Coeff. of permeability (k)
| i = | = | = 0.01667 | ||
| L | 1.5 × 10³ |
k = 30 m/d
∴ V = 30 × 0.01667 = 0.5 m/d
| Actual velocity, Vs = | = | = 2 m/d | ||
| η | 0.25 |
| Time of travel = | = | = 750 | ||
| Vs | 2 |
