CSM Erosion & Sediment Control Flashcards
6 cards from real CSM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CSM Erosion & Sediment Control flashcards as text
What is the maximum recommended drainage area for a standard silt fence installation?
Answer: 0.25 acres per 100 feet of fence
Industry guidance limits silt fence drainage area to approximately 0.25 acres per 100 linear feet to prevent overtopping and structural failure during storm events.
What is the primary use of fiber rolls (wattles) in erosion and sediment control?
Answer: To intercept slope runoff and capture sediment along the contour of a disturbed slope
Fiber rolls are placed along contours on disturbed slopes to slow runoff velocity, spread flow, and trap sediment moving downslope.
What is turbidity and why is it a key indicator in stormwater management?
Answer: Cloudiness of water caused by suspended particles; high turbidity indicates sediment pollution and can harm aquatic life
Turbidity measures water cloudiness from suspended sediment and other particles; elevated turbidity in receiving waters harms aquatic ecosystems and is often regulated under NPDES permits.
What is the fundamental difference between erosion and sedimentation?
Answer: Erosion is the detachment and transport of soil particles; sedimentation is the deposition of those transported particles
Erosion detaches soil particles from the ground surface through water or wind energy, while sedimentation is the settling and deposition of those transported particles at a new location.
According to general NPDES Construction General Permit requirements, how often must sediment controls be inspected?
Answer: At least every 7 days and within 24 hours after a storm event of 0.5 inches or more
Most Construction General Permits require inspections at least every 7 calendar days and within 24 hours after qualifying storm events to ensure controls are functioning properly.
How does soil compaction on a construction site affect erosion potential?
Answer: Compaction reduces infiltration, increasing surface runoff volume and velocity, which can increase erosion on unprotected areas
Compacted soils have reduced porosity and infiltration capacity, so more rainfall becomes surface runoff with greater erosive potential on unprotected areas downslope.