CSM Hydrology & Watershed Management 2

Question 1

Which hydrologic process describes the movement of water from the soil surface into the soil profile?

Accepted Answer

Infiltration

Answer

Infiltration is the process by which water on the ground surface enters the soil, while percolation refers to downward movement through the saturated zone.

Question 2

A watershed with a curve number (CN) of 90 compared to one with CN of 60 will produce:

Accepted Answer

More runoff for the same rainfall event

Answer

Higher curve numbers indicate less permeable, more developed or compacted land, resulting in greater direct runoff for the same precipitation event.

Question 3

What is the term for the portion of precipitation that eventually reaches a stream channel through shallow subsurface flow?

Accepted Answer

Interflow

Answer

Interflow (also called subsurface stormflow or throughflow) moves laterally through the upper soil horizons and contributes to streamflow during and shortly after storms.

Question 4

The rational method formula Q = CiA requires that the storm duration equal the time of concentration because:

Accepted Answer

The entire watershed contributes runoff simultaneously at peak flow

Answer

When storm duration equals time of concentration, all parts of the watershed are contributing simultaneously, producing the maximum peak discharge for that rainfall intensity.

Question 5

Which factor most directly reduces the lag time between precipitation and peak streamflow in an urbanized watershed?

Accepted Answer

Increased impervious cover and storm sewer networks

Answer

Impervious surfaces and storm sewers speed overland and channel flow, shortening the time for water to travel from the watershed to the outlet.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Hydrology & Watershed Management 2