CPESC Construction Site Controls 2 — Questions and Answers
Question 1: What is the primary purpose of a stabilized construction entrance/exit?
- To provide a paved roadway for heavy equipment
- To reduce the tracking of sediment onto public roads by vehicles leaving the site (Correct answer)
- To prevent stormwater from entering the construction site
- To designate a safe pedestrian crossing zone
Correct answer: To reduce the tracking of sediment onto public roads by vehicles leaving the site
Stabilized construction entrances use coarse aggregate or rumble strips to dislodge mud and debris from vehicle tires before they reach public roads.
Question 2: During active grading on a construction site, which practice best protects exposed soil from raindrop splash erosion?
- Installing perimeter silt fencing
- Applying a hydraulic mulch tackifier to bare soil (Correct answer)
- Constructing check dams in drainage channels
- Grading slopes to a 3:1 ratio
Correct answer: Applying a hydraulic mulch tackifier to bare soil
Hydraulic mulch with tackifier provides immediate surface protection by absorbing raindrop impact energy and reducing soil particle detachment.
Question 3: Which document typically establishes the legal framework for stormwater discharges from construction sites in the US?
- The Clean Air Act Section 112
- The National Pollutant Discharge Elimination System (NPDES) Construction General Permit (Correct answer)
- The Resource Conservation and Recovery Act
- The Safe Drinking Water Act
Correct answer: The National Pollutant Discharge Elimination System (NPDES) Construction General Permit
The NPDES Construction General Permit issued under the Clean Water Act governs stormwater discharges from construction activities disturbing one or more acres.
Question 4: A site inspector notices that a silt fence has been installed with the fabric stapled tightly to the post with no slack. What problem does this create?
- The fence will fail to intercept runoff because the openings are too large
- The fabric cannot flex and will be more prone to blowout under hydrostatic pressure (Correct answer)
- The installation is correct and requires no modification
- The fence will trap too much sediment and clog prematurely
Correct answer: The fabric cannot flex and will be more prone to blowout under hydrostatic pressure
Fabric installed without slack cannot deflect under ponded water pressure, concentrating stress at staple points and increasing the risk of failure.
Question 5: What is the recommended maximum drainage area for a typical silt fence installation?
- 5 acres
- 0.25 acres per 100 linear feet of fence (Correct answer)
- 2 acres
- 10 acres
Correct answer: 0.25 acres per 100 linear feet of fence
Silt fence is generally designed for small drainage areas, typically no more than 0.25 acres per 100 linear feet, to prevent overtopping and failure.
Question 6: Which of the following construction site controls is considered a 'source control' rather than a 'conveyance or treatment control'?
- Sediment basin
- Vegetated swale
- Phased grading to minimize disturbed area (Correct answer)
- Silt fence along the perimeter
Correct answer: Phased grading to minimize disturbed area
Phased grading limits the amount of disturbed soil at any one time, reducing erosion at the source rather than capturing sediment after it has been mobilized.
Question 7: A construction site has a 3:1 (H:V) cut slope that is 30 feet tall. What is the primary concern for long-term slope stability?
- The slope angle is too gentle and will erode slowly
- Seepage forces and increased pore water pressure can trigger deep-seated slope failure (Correct answer)
- The slope is stable and vegetation alone will provide adequate protection
- Surface rilling will be the only form of erosion on this slope
Correct answer: Seepage forces and increased pore water pressure can trigger deep-seated slope failure
Tall cut slopes are vulnerable to deep-seated failures driven by elevated pore water pressures, especially in fine-grained soils, requiring both drainage and vegetation measures.
CPESC Construction Site Controls 2
What is the primary purpose of a stabilized construction entrance/exit?