Erosion & Sediment Control Principles Flashcards
7 cards from real CESSWI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Erosion & Sediment Control Principles flashcards as text
Which factor in the RUSLE equation accounts for the ability of soil to resist detachment and transport by rainfall?
Answer: K factor (soil erodibility)
The K factor in RUSLE represents soil erodibility, reflecting the soil's susceptibility to detachment and transport by rainfall and runoff.
A contractor installs a silt fence parallel to the slope contours on a 15% grade. What is the primary concern with this installation?
Answer: Silt fence is not recommended for slopes exceeding 10%
Silt fences are generally not recommended on slopes steeper than 10% because concentrated flow can overwhelm the barrier and cause failure.
During a post-storm inspection, an inspector finds that a sediment basin outlet riser pipe is submerged and the basin is overtopping the embankment. What is the most likely cause?
Answer: Inadequate principal spillway capacity for the storm event
Overtopping an embankment during a storm typically indicates the principal spillway was undersized and cannot convey the runoff generated by that event.
Which erosion mechanism involves the removal of a thin, relatively uniform layer of soil from the land surface by raindrop splash and sheet flow?
Answer: Sheet erosion
Sheet erosion removes a thin, fairly uniform layer of soil across a broad area through the combined action of raindrop impact and shallow overland flow.
A SWPPP requires a sediment trap to be sized for a drainage area of 2 acres. Using a volumetric standard of 1,800 cubic feet per acre, what minimum storage volume is required?
Answer: 3,600 cubic feet
Multiplying the 2-acre drainage area by 1,800 cubic feet per acre yields a required storage volume of 3,600 cubic feet.
Which of the following best describes the purpose of an anti-seep collar on a sediment basin outlet barrel?
Answer: To lengthen the seepage path and reduce piping failure risk
Anti-seep collars extend the seepage path along the outside of the barrel through the embankment, reducing hydraulic gradient and the risk of internal erosion (piping).
A construction site experiences a severe rain event that causes sediment to discharge into an adjacent stream. Under NPDES permit conditions, what is the operator's immediate obligation?
Answer: Document the event and notify the permitting authority within the required timeframe
NPDES permits typically require operators to document unauthorized discharges and report them to the permitting authority within a specified timeframe (often 24–72 hours).