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 hydroseeding as an erosion control method?
Answer: A process that sprays a slurry of seed, mulch, fertilizer, and water onto disturbed soil to establish vegetation quickly
Hydroseeding applies a hydraulically sprayed mixture of seed, mulch, fertilizer, and sometimes tackifier to rapidly establish vegetative cover on disturbed areas.
What is a sediment trap, and how does it differ from a sediment basin?
Answer: A sediment trap is a small, excavated or bermed impoundment for drainage areas under 5 acres; a sediment basin serves larger areas with more engineered design
Sediment traps are smaller, simpler impoundments designed for drainage areas up to about 5 acres, while sediment basins are larger engineered structures for bigger contributing areas with outlet control structures.
What is the recommended minimum percent vegetative cover that should be achieved before temporary erosion controls are removed from a site?
Answer: 70% uniform vegetative cover over the disturbed area
Most regulatory guidance requires at least 70% uniform vegetative ground cover before temporary erosion and sediment controls can be removed from a disturbed area.
What is the purpose of a diversion dike or ridge in construction site erosion control?
Answer: To intercept upslope runoff and redirect it around a disturbed area to prevent erosion and reduce sediment loading
Diversion dikes intercept runoff flowing toward a disturbed area from upslope and redirect it safely around the construction zone to a stable outlet.
Which condition requires immediate repair of a silt fence according to maintenance standards?
Answer: Sediment accumulation reaching one-third the height of the fence
When sediment builds up to one-third of the fence height, the fence is nearing its capacity and must be cleaned out or repaired to maintain effectiveness and prevent overtopping or blowout.
What role does soil texture play in determining erosion susceptibility on a construction site?
Answer: Fine-grained silty soils are generally the most erodible because particles are easily detached and transported by water
Silt-sized particles are the most erodible because they lack the cohesion of clay but are fine enough to be easily suspended and transported by rainfall and runoff.