CESSWI Soil Properties and Site Characterization Flashcards
6 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 6 CESSWI Soil Properties and Site Characterization flashcards as text
Which soil amendment is most commonly applied on disturbed sites to improve soil structure, water retention, and support of vegetation establishment?
Answer: Compost or organic matter
Compost and organic matter improve soil aggregation, increase water-holding capacity, supply nutrients, and promote microbial activity that accelerates vegetation establishment.
A 'perched water table' on a construction site is most likely caused by:
Answer: An impermeable soil or rock layer that impedes downward percolation of water
A perched water table forms when a low-permeability layer (clay lens, hardpan, or bedrock) traps infiltrating water above the regional water table.
When evaluating a site's susceptibility to rill erosion, which combination of factors poses the greatest risk?
Answer: Steep slopes, bare silt loam soil, high-intensity rainfall
Rill erosion is maximized by steep slopes that accelerate flow velocity, highly erodible silt loam, bare conditions with no protective cover, and high-intensity rain events.
For site characterization purposes, what does the term 'time of concentration' (Tc) describe?
Answer: The time for runoff to travel from the hydraulically most distant point of the watershed to the outlet
Time of concentration determines when the entire watershed contributes runoff to the outlet, which is critical for calculating peak discharge rates and sizing BMPs.
Soil texture is determined by the relative proportions of which three particle sizes?
Answer: Sand, silt, and clay
USDA soil texture classification is based on the percentages of sand (0.05–2 mm), silt (0.002–0.05 mm), and clay (<0.002 mm) as plotted on a soil texture triangle.
During a site walk, an inspector observes a whitish crust on the soil surface in a low-lying area. This is most likely an indication of:
Answer: Salt accumulation (efflorescence) from high soil sodicity or evaporation of mineralized water
White salt crusts on soil surfaces indicate high sodium or other soluble salt concentrations, which can cause soil dispersion and impede vegetation establishment.