What is the term for the time required by a raindrop from the hydraulically most remote point to reach the outlet of a drainage basin?

• A. A) Time of concentration
• B. B) Lag time
• C. C) Peak time
• D. D) None of the above

Answer: (A)

The term for the time required by a raindrop from the hydraulically most remote point to reach the outlet of a drainage basin is known as the time of concentration. This concept is fundamental in hydrology and stormwater management as it helps in estimating how quickly water will flow through a drainage area during a rainfall event.

Time of concentration takes into account the various routes that water can take within the watershed, factoring in variables such as slope, velocity, and land cover. By understanding this time, engineers and planners can better design drainage systems and predict peak runoff conditions.

In contrast, lag time refers to the time difference between the center of mass of rainfall and the peak flow at the outlet, which is distinct from the time of concentration. Peak time typically refers to the moment when the maximum discharge occurs in the system after a rain event, also different from the time measured for a raindrop’s journey to the outlet. None of the above would imply that none of the terms apply, but since time of concentration accurately describes this phenomenon, it confirms the relevance of using the correct terminology in water management contexts.