CME Stormwater Management & Drainage Engineering 3

Question 1

What is the primary hydraulic purpose of a culvert in municipal stormwater infrastructure?

Accepted Answer

To convey stormwater flow under a roadway or embankment while maintaining road integrity

Answer

To detain stormwater and reduce peak discharge rates

Answer

To filter sediment and pollutants from runoff before discharge

Answer

To serve as an energy dissipator at the base of steep slopes

Question 2

Which design storm return period is most commonly specified for sizing major storm drainage infrastructure such as trunk lines and culverts in US municipalities?

Accepted Answer

10-year or 25-year return period

Answer

1-year return period

Answer

500-year return period

Answer

2-year return period

Question 3

Peak discharge in a watershed is influenced by all of the following EXCEPT:

Accepted Answer

The color of pavement used on impervious surfaces

Answer

Watershed area and shape

Answer

Land use and percent impervious cover

Answer

Storm duration and intensity

Question 4

A sediment basin on a construction site is designed primarily to:

Accepted Answer

Allow sediment to settle out of stormwater runoff before it is discharged off-site

Answer

Store stormwater for reuse in construction activities

Answer

Prevent erosion on exposed soil slopes

Answer

Capture petroleum hydrocarbons from equipment yards

Question 5

In stormwater basin design, 'freeboard' refers to:

Accepted Answer

The vertical distance between the design water surface elevation and the top of the embankment

Answer

The overflow weir length used to pass the design storm

Answer

The distance between the basin outlet and the downstream waterway

Answer

The storage volume available below the permanent pool

Question 6

Under FEMA's National Flood Insurance Program (NFIP), a Special Flood Hazard Area (SFHA) is defined as land subject to inundation by a flood event with what probability of occurrence in any given year?

Accepted Answer

1% or greater annual chance (100-year flood)

Answer

0.2% annual chance (500-year flood)

Answer

2% annual chance (50-year flood)

Answer

10% annual chance (10-year flood)

Question 7

Impervious cover in a watershed is significant to stormwater engineers because it:

Accepted Answer

Increases runoff volume and peak discharge while decreasing infiltration and groundwater recharge

Answer

Increases evapotranspiration rates compared to vegetated land

Answer

Reduces the time of concentration by promoting sheet flow across the surface

Answer

Decreases the runoff coefficient used in peak flow calculations