CPESC Construction Site Controls 5 — Questions and Answers
Question 1: Which erosion control measure is most effective for protecting a freshly seeded slope from raindrop impact and overland flow during the germination period?
- Silt fence at the toe of slope
- Erosion control blanket (ECB) pinned over the seeded area (Correct answer)
- Rock check dams in adjacent channels
- Perimeter berm of compacted soil
Correct answer: Erosion control blanket (ECB) pinned over the seeded area
Erosion control blankets physically protect seed and soil from rainfall impact and surface flow while allowing germination and plant establishment.
Question 2: A CPESC professional is reviewing a site where runoff from an asphalt millings stockpile is entering a storm drain. What is the primary pollution concern?
- Excessive turbidity from asphalt particle suspension
- Elevated pH from lime additives in old asphalt
- Polycyclic aromatic hydrocarbons (PAHs) leaching from the millings into stormwater (Correct answer)
- Increased water temperature from the dark-colored material
Correct answer: Polycyclic aromatic hydrocarbons (PAHs) leaching from the millings into stormwater
Asphalt millings contain PAHs, which are toxic organic compounds that can leach into stormwater and cause significant harm to aquatic ecosystems.
Question 3: What is the purpose of a 'construction limit of disturbance' (LOD) line on a grading plan?
- To show the final grade elevation of the finished site
- To define the boundary beyond which no clearing, grading, or soil disturbance is permitted (Correct answer)
- To mark the location of underground utilities
- To indicate where sediment basins must be placed
Correct answer: To define the boundary beyond which no clearing, grading, or soil disturbance is permitted
The LOD line restricts disturbance to the minimum necessary area, thereby protecting adjacent undisturbed land and reducing the total area requiring erosion and sediment controls.
Question 4: During a site inspection after a storm, an inspector observes that a sediment basin's emergency spillway has been activated. What does this indicate?
- The basin is functioning correctly and has adequate capacity
- The basin received a runoff volume exceeding its design storm capacity, suggesting it may be undersized or partially clogged (Correct answer)
- The primary outlet pipe has failed completely
- The inspector should immediately remove sediment from the basin
Correct answer: The basin received a runoff volume exceeding its design storm capacity, suggesting it may be undersized or partially clogged
Emergency spillway activation indicates the basin's primary outlet was overwhelmed, which may signal the basin is undersized, sediment-full, or that the storm exceeded the design event.
Question 5: Which construction activity typically requires a separate individual NPDES permit rather than coverage under the Construction General Permit?
- A 50-acre residential subdivision grading project
- A highway interchange construction project disturbing 200 acres with complex discharge requirements (Correct answer)
- A commercial building site disturbing 3 acres
- A single-family home construction on a 0.5-acre lot in a common plan of development
Correct answer: A highway interchange construction project disturbing 200 acres with complex discharge requirements
Large, complex projects with unique or significant discharge conditions may require an individual NPDES permit tailored to their specific circumstances rather than the standard CGP.
Question 6: What is 'sheet flow' erosion and why is it significant in construction site management?
- Erosion caused by heavy machinery compressing the soil surface
- Thin, uniform overland flow of water that detaches and transports sediment across bare graded surfaces (Correct answer)
- Erosion from concentrated stream channel flow undercutting banks
- Erosion caused by wind moving dry soil particles off-site
Correct answer: Thin, uniform overland flow of water that detaches and transports sediment across bare graded surfaces
Sheet flow erodes the surface uniformly across wide areas of bare soil; on construction sites, it is a major sediment source before concentrated flow patterns develop.
Question 7: A construction SWPPP includes a 'BMP implementation schedule.' What is the primary regulatory purpose of this schedule?
- To track the cost of installing erosion and sediment controls
- To document when specific controls will be installed relative to construction activities, demonstrating compliance sequencing (Correct answer)
- To schedule routine maintenance of permanent stormwater infrastructure
- To coordinate BMP installation with weather forecasts
Correct answer: To document when specific controls will be installed relative to construction activities, demonstrating compliance sequencing
The BMP implementation schedule demonstrates to regulators that controls will be in place before and during the activities that generate potential discharges, ensuring sequenced compliance.
CPESC Construction Site Controls 5
Which erosion control measure is most effective for protecting a freshly seeded slope from raindrop impact and overland flow during the germination period?