LARE LARE Prep Section 2 — Questions and Answers
Question 1: When grading a site to direct stormwater away from a building foundation, the minimum recommended slope for the first 10 feet from the structure is:
- 1%
- 2%
- 5% (Correct answer)
- 10%
Correct answer: 5%
A minimum 5% slope (6 inches per 10 feet) is required for the first 10 feet away from a building foundation to prevent water infiltration.
Question 2: Under the Americans with Disabilities Act (ADA), the maximum running slope for an accessible route that does NOT qualify as a ramp is:
- 2%
- 5%
- 8.33% (Correct answer)
- 12%
Correct answer: 8.33%
An accessible route with a slope exceeding 5% is considered a ramp, so the maximum running slope for a non-ramp route is 8.33% (1:12).
Question 3: Which contour interval is most appropriate for a large-scale grading plan of a residential lot with moderate topographic variation?
- 0.5 feet
- 1 foot (Correct answer)
- 5 feet
- 10 feet
Correct answer: 1 foot
A 1-foot contour interval provides sufficient detail for residential-scale grading without excessive line density on moderate terrain.
Question 4: A landscape architect is designing a bioretention basin. The typical ponding depth allowed before overflow should not exceed:
- 6 inches
- 12 inches (Correct answer)
- 18 inches
- 24 inches
Correct answer: 12 inches
Bioretention basins are typically designed for a maximum ponding depth of 12 inches to ensure proper infiltration and plant survival.
Question 5: In construction documentation, a 'spot elevation' shown as 103.75 on a grading plan indicates:
- The elevation is 103 feet 75 inches above sea level
- The finished grade elevation is 103.75 feet above a datum (Correct answer)
- The cut depth is 3.75 feet from existing grade 100
- The slope ratio is 103:75
Correct answer: The finished grade elevation is 103.75 feet above a datum
A spot elevation indicates the finished grade elevation at a specific point, measured in feet above a reference datum.
Question 6: Which of the following stormwater management practices is considered a 'green infrastructure' or Low Impact Development (LID) approach?
- Underground detention vault
- Concrete lined drainage channel
- Permeable pavement with infiltration bed (Correct answer)
- Corrugated metal pipe culvert
Correct answer: Permeable pavement with infiltration bed
Permeable pavement with an infiltration bed mimics natural hydrology by allowing water to infiltrate on-site, a core principle of LID.
Question 7: The 'time of concentration' in stormwater hydrology refers to:
- The time for a pollutant to reach a concentration limit
- The time for runoff to travel from the hydraulically farthest point to the outlet (Correct answer)
- The duration of the design storm event
- The time required for soil to reach saturation
Correct answer: The time for runoff to travel from the hydraulically farthest point to the outlet
Time of concentration is the travel time of stormwater from the most hydraulically remote point in the watershed to the design outlet.
LARE LARE Prep Section 2
When grading a site to direct stormwater away from a building foundation, the minimum recommended slope for the first 10 feet from the structure is: