LARE LARE Drainage System Design 3

Question 1

A landscape architect is designing a rain garden on a residential lot with silty clay soils. Which modification is most appropriate to improve performance?

Accepted Answer

Amend native soil with compost and sand to improve infiltration

Answer

Amending heavy clay soils with compost and sand increases infiltration rates, which is essential for rain garden function.

Question 2

In the Rational Method (Q = CiA), what does the runoff coefficient 'C' represent?

Accepted Answer

The fraction of rainfall that becomes surface runoff

Answer

The runoff coefficient C represents the proportion of rainfall that becomes surface runoff, ranging from 0 (no runoff) to 1 (all rainfall runs off).

Question 3

Which stormwater BMP is best suited to treat highway runoff containing petroleum hydrocarbons and heavy metals?

Accepted Answer

Underground hydrodynamic separator

Answer

Hydrodynamic separators are effective at removing sediment-bound metals and hydrocarbons from concentrated highway runoff in space-constrained sites.

Question 4

What is the primary purpose of a flared end section (FES) at a culvert outlet?

Accepted Answer

To reduce outlet velocity and minimize erosion at the discharge point

Answer

A flared end section spreads and slows the discharge, reducing scour and erosion at the culvert outlet.

Question 5

During a grading review, a plan shows a drainage divide running through the center of a proposed parking lot. What does this mean for stormwater design?

Accepted Answer

Runoff flows in two directions toward separate drainage systems or outfalls

Answer

A drainage divide is the high point from which runoff flows in opposite directions, requiring separate stormwater management for each drainage area.

LARE Test Practice Test

LARE Test Practice Test

LARE LARE Drainage System Design 3