CPESC Site Assessment & Planning 5 — Questions and Answers
Question 1: In site planning for erosion control, what is the primary purpose of establishing a 'construction limit of disturbance' (LOD) line on the plan?
- To define the boundary of the surveyed property
- To clearly delineate where land disturbance activities are permitted to occur (Correct answer)
- To mark the edge of the required buffer zones from streams
- To indicate where final grading will match existing grade
Correct answer: To clearly delineate where land disturbance activities are permitted to occur
The LOD line defines the maximum extent of land disturbance, helping prevent unnecessary clearing and grading beyond what is needed for the project.
Question 2: Which hydrologic soil group (HSG) produces the greatest amount of runoff from a given rainfall event?
- Group A (deep, well-drained sands)
- Group B (moderately deep, well-drained silts)
- Group C (shallow soils with low infiltration)
- Group D (clays with very low infiltration rates) (Correct answer)
Correct answer: Group D (clays with very low infiltration rates)
HSG D soils (expansive clays, shallow soils over impervious layers) have the lowest infiltration rates and generate the most runoff per unit of rainfall.
Question 3: When assessing an existing graded stockpile for erosion risk, which factor most increases the urgency of implementing temporary stabilization?
- The stockpile is located more than 100 feet from a property boundary
- The stockpile has been inactive for more than 14 days and rain is forecast (Correct answer)
- The stockpile material consists primarily of gravel and coarse sand
- The stockpile is surrounded by established vegetative cover
Correct answer: The stockpile has been inactive for more than 14 days and rain is forecast
Most regulations require temporary stabilization of disturbed areas and stockpiles within 14 days of inactivity, especially when rainfall is imminent.
Question 4: A site assessment for a linear project (pipeline) across multiple soil types should prioritize which planning approach?
- Using a single standard BMP for the entire project length
- Segmenting the project by soil type, slope, and drainage area for BMP selection (Correct answer)
- Installing all BMPs before any grading begins project-wide
- Completing full revegetation on one segment before disturbing the next
Correct answer: Segmenting the project by soil type, slope, and drainage area for BMP selection
Linear projects cross diverse conditions, so segmenting by soil type, slope, and drainage characteristics allows BMPs to be tailored to actual site conditions in each segment.
Question 5: Under the EPA's Construction General Permit (CGP), what is the minimum frequency for routine site inspections during active construction?
- Daily during rain events only
- At least once every 7 calendar days (Correct answer)
- At least once every 14 calendar days
- Monthly unless a storm event occurs
Correct answer: At least once every 7 calendar days
The EPA CGP requires inspections at least every 7 calendar days and within 24 hours of a storm event of 0.25 inches or more.
Question 6: A CPESC practitioner reviewing site plans notices that a proposed grading plan will direct all site runoff to a single outlet point. The primary risk this creates is:
- Insufficient infiltration across the site
- Concentrated discharge that may cause erosion at the outlet and downstream (Correct answer)
- Reduced opportunity to collect sediment across the site
- Non-compliance with stormwater volume reduction requirements
Correct answer: Concentrated discharge that may cause erosion at the outlet and downstream
Concentrating all runoff at a single outlet creates high-velocity discharge that can cause scour and channel erosion at the outlet and in the downstream receiving channel.
Question 7: Which information from a site assessment is most critical for determining the appropriate seed mix for temporary stabilization?
- Soil pH, drainage class, and the expected stabilization duration (Correct answer)
- The brand of erosion control blanket to be used as a companion BMP
- The RUSLE C-factor for the proposed vegetation type
- The distance from the nearest certified seed dealer
Correct answer: Soil pH, drainage class, and the expected stabilization duration
Soil pH, drainage class, and expected duration guide selection of a seed mix that will germinate quickly and establish effectively under the site's specific conditions.
CPESC Site Assessment & Planning 5
In site planning for erosion control, what is the primary purpose of establishing a 'construction limit of disturbance' (LOD) line on the plan?