Stormwater Management & Drainage Engineering Flashcards
7 cards from real CME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Stormwater Management & Drainage Engineering flashcards as text
What is the primary hydraulic purpose of a culvert in municipal stormwater infrastructure?
Answer: To convey stormwater flow under a roadway or embankment while maintaining road integrity
A culvert is a conduit (pipe, box, or arch) that carries a waterway or stormwater flow beneath a roadway, embankment, or other obstruction without disrupting the surface infrastructure.
Which design storm return period is most commonly specified for sizing major storm drainage infrastructure such as trunk lines and culverts in US municipalities?
Answer: 10-year or 25-year return period
Most municipal design standards specify a 10-year or 25-year return period for major storm drainage systems such as trunk lines, culverts, and channels, balancing cost and flood protection for infrastructure.
Peak discharge in a watershed is influenced by all of the following EXCEPT:
Answer: The color of pavement used on impervious surfaces
Pavement color does not affect peak discharge calculations; peak discharge is governed by watershed area, land use (imperviousness), topography affecting flow paths, and rainfall characteristics.
A sediment basin on a construction site is designed primarily to:
Answer: Allow sediment to settle out of stormwater runoff before it is discharged off-site
A sediment basin uses detention time to allow suspended sediment particles to settle by gravity before stormwater is discharged, reducing turbidity and total suspended solids in construction site runoff.
In stormwater basin design, 'freeboard' refers to:
Answer: The vertical distance between the design water surface elevation and the top of the embankment
Freeboard is the vertical distance between the maximum design water surface elevation and the top of the dam or embankment, providing a safety margin against overtopping from events exceeding the design storm.
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?
Answer: 1% or greater annual chance (100-year flood)
FEMA designates Special Flood Hazard Areas as zones with a 1% or greater annual chance of flooding (the 100-year or base flood), which forms the basis for mandatory flood insurance purchase requirements and floodplain management regulations.
Impervious cover in a watershed is significant to stormwater engineers because it:
Answer: Increases runoff volume and peak discharge while decreasing infiltration and groundwater recharge
Impervious surfaces such as roads, rooftops, and parking lots prevent rainfall from infiltrating, increasing both the volume and peak rate of stormwater runoff, which stresses drainage infrastructure and degrades stream health.