LARE Stormwater Management Questions and Answers

Question 1

A landscape architect is designing a stormwater management system for a commercial development.
The design includes a large detention basin.
What is the primary function of a forebay within this system?

Accepted Answer

To capture and settle coarse sediments before they enter the main basin.

Answer

To provide a dedicated area for wildlife habitat.

Answer

To increase the peak discharge rate from the basin.

Answer

To store the entire water quality volume (WQv) of the design storm.

Question 2

Which of the following Low Impact Development (LID) techniques primarily functions to reduce stormwater runoff volume and mitigate the urban heat island effect by utilizing a building's roof surface?

Accepted Answer

Green Roof

Answer

Permeable Pavers

Answer

Bioretention Cell

Answer

Rainwater Cistern

Question 3

In designing a grass-lined swale for a new park, the landscape architect specifies a series of check dams. What is the principal reason for including check dams in this context?

Accepted Answer

To reduce the velocity of water flow, preventing channel erosion and promoting infiltration.

Answer

To increase water velocity and flush sediments.

Answer

To create a series of deep ponds for aquatic life.

Answer

To serve as the primary sediment trapping device for the entire site.

Question 4

A landscape architect is specifying the bioretention soil media (BSM) for a series of rain gardens. To ensure proper function, what is a critical performance requirement for this specialized soil mix?

Accepted Answer

A minimum long-term infiltration rate of at least 5 inches per hour.

Answer

A high clay content to maximize water retention.

Answer

Compaction to at least 98% of its maximum dry density.

Answer

A composition of 80% compost and 20% sand to boost nutrient levels.

Question 5

When calculating peak stormwater runoff for a small watershed (less than 20 acres) using the Rational Method (Q=CiA), what does the runoff coefficient 'C' represent?

Accepted Answer

A dimensionless fraction representing the portion of rainfall that becomes direct runoff.

Answer

The total volume of rainfall in cubic feet.

Answer

The time it takes for runoff to travel from the most distant point of the watershed.

Answer

The average intensity of rainfall in inches per hour.

Question 6

A landscape architect needs to transition concentrated stormwater flow from a pipe outlet to gentle sheet flow across a stabilized vegetated slope to prevent erosion. Which stormwater management device is specifically designed for this purpose?

Accepted Answer

Level Spreader

Answer

Catch Basin

Answer

Riprap Apron

Answer

Infiltration Trench