CLA Grading & Drainage Flashcards

Which method is used to calculate the volume of cut and fill earthwork on a grading project?

Answer: Prismoidal formula or average end area

Earthwork volumes are commonly estimated using the average end area method or the more accurate prismoidal formula.

A retention pond holds stormwater permanently, while a detention pond:

Answer: Temporarily stores water and releases it slowly

A detention pond temporarily detains stormwater and releases it at a controlled rate through an outlet structure.

What slope range is typically considered the maximum for mown grass areas accessible to riding mowers?

Answer: 5–10%

Riding mowers can safely operate on slopes up to about 10%, above which hand mowers or groundcovers are recommended.

In grading plans, what does 'FF 101.50' typically indicate?

Answer: Finish floor elevation

FF stands for finished floor elevation, which must sit above the surrounding grade to prevent water intrusion.

Which bioretention feature is designed to temporarily pond water and allow it to infiltrate through a soil media layer?

Answer: Rain garden

Rain gardens are shallow, vegetated depressions filled with engineered media that allow stormwater to infiltrate and be filtered.

What is the term for the elevation difference between the inlet and outlet of a culvert expressed as a percentage?

Answer: Pipe slope

Pipe slope is the vertical drop divided by the pipe length × 100, and it governs flow velocity within the culvert.