CSM Hydrology & Watershed Management 3

Question 1

Which soil hydrologic group has the highest runoff potential and lowest infiltration rate when thoroughly wet?

Accepted Answer

Group D

Answer

Hydrologic Soil Group D consists of soils with very slow infiltration rates (clay soils or soils with a high water table) and produces the highest runoff.

Question 2

The concept of 'bankfull discharge' is significant in watershed management because it:

Accepted Answer

Is the flow that does the most geomorphic work and shapes the channel

Answer

Bankfull discharge, typically corresponding to the 1.5- to 2-year return interval, is responsible for transporting the most sediment and maintaining channel form over time.

Question 3

What is the primary purpose of a unit hydrograph in stormwater hydrology?

Accepted Answer

To relate a unit depth of excess rainfall to a direct runoff hydrograph for a watershed

Answer

A unit hydrograph represents the direct runoff response of a watershed to one unit (1 inch or 1 cm) of excess rainfall uniformly distributed over the watershed for a specified duration.

Question 4

Which of the following best describes the 'baseflow recession' portion of a streamflow hydrograph?

Accepted Answer

The slow drainage of groundwater into the stream after storm runoff has ceased

Answer

Baseflow recession represents the gradual depletion of groundwater storage that sustains streamflow between storm events, typically following an exponential decay pattern.

Question 5

A developer proposes to fill a wetland that provides 50 acre-feet of floodwater storage. Under the watershed management perspective, this action would most likely:

Accepted Answer

Increase downstream flood peaks by eliminating natural detention storage

Answer

Wetlands attenuate flood peaks by temporarily storing floodwater; eliminating this storage increases and accelerates downstream runoff, raising peak flows.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Hydrology & Watershed Management 3