NASCLA Accredited Commercial General ContractorSite WorkMedium
A site superintendent is reviewing plans for a new commercial parking lot. The design specifies that the finished grade of the parking lot must have a minimum slope of 1.5% for proper drainage. If the parking lot is 200 feet long in the direction of the slope, what is the minimum required elevation change from one end to the other?
- A3.0 feet
- B30.0 feet
- C1.5 feet
- D0.3 feet
Show answer & explanationAnswer & explanation
Correct answer: A. 3.0 feet
Slope percentage is calculated as (rise / run) * 100. To find the rise (elevation change), rearrange the formula: Rise = (Slope % / 100) * Run. So, Rise = (1.5 / 100) * 200 feet = 0.015 * 200 feet = 3.0 feet.
Why the other options are wrong
- B. This would be a 15% slope, which is too steep for a parking lot. (30/200)*100 = 15%
- C. This would be a 0.75% slope, which is too low. (1.5/200)*100 = 0.75%
- D. This would be a 0.15% slope, which is too low. (0.3/200)*100 = 0.15%
Slope Calculation (Percentage)
Slope percentage is a measure of the steepness of a surface, expressed as the ratio of vertical rise to horizontal run, multiplied by 100.
- Formula: Slope % = (Rise / Run) * 100.
- Used in grading for drainage, accessibility, and aesthetics.
- Expressed as a percentage (e.g., 2%).
Memory trick: Rise over Run, Times a Hundred, That's Your Slope.