List of top Water Resources and Environmental Hydraulics Questions

A 6-hour rainfall of 6 cm at a station was found to have a return period of 40 years. The probability that a 6-hour rainfall of this or larger magnitude will occur at least once in 20 successive years at that station is ______ (rounded off to three decimal places).

A well penetrates an unconfined aquifer. The water level (i.e., head) in the well prior to pumping is 25 m. After a long period of pumping at a constant rate of 0.05 m³/s, the drawdowns at distances of 50 m and 150 m from the well are observed to be 3 m and 1.2 m, respectively.
The hydraulic conductivity of the unconfined aquifer is ______ × 10^-4 m/s (rounded off to two decimal places).
Consider π = 3.14.

The mass curve of a rainfall event of 100 min duration over a catchment is given in the table.

Time from start of rainfall (min)	0	20	40	60	80	100
Cumulative rainfall (cm)	0	0.5	1.2	2.6	3.3	3.5

If the initial loss is 0.6 cm and φ-index is 0.6 cm/hour, the total surface runoff from the catchment is ______ cm (rounded off to one decimal place).

Which one of the following gases is primarily responsible for the formation of photochemical smog?

Which of the following is the first step in Environmental Impact Assessment (EIA)?