BLArch Bachelor of Landscape Architecture Grading and Drainage

Question 1

What is the minimum recommended slope away from a building foundation to ensure positive drainage?

Accepted Answer

2% for 10 feet

Answer

A minimum 2% slope (2 inches of fall per 10 feet) away from building foundations is the standard to direct water away and prevent infiltration.

Question 2

In landscape grading, what does the term 'spot elevation' refer to?

Accepted Answer

A specific elevation noted at a precise point on a plan

Answer

A spot elevation is a specific elevation value noted at a precise location on a grading plan, used to define critical high and low points.

Question 3

What is the formula for calculating percent slope?

Accepted Answer

Rise ÷ Run × 100

Answer

Percent slope = (Rise ÷ Run) × 100, where rise is the vertical change and run is the horizontal distance.

Question 4

Which type of drainage system collects surface runoff through underground perforated pipes?

Accepted Answer

French drain

Answer

A French drain uses perforated pipe surrounded by gravel to collect and redirect subsurface or surface water away from problem areas.

Question 5

A 'swale' in site drainage is best described as:

Accepted Answer

A shallow, vegetated channel that conveys stormwater

Answer

A swale is a shallow, gently sloping, vegetated channel designed to slow, filter, and convey stormwater runoff across a site.

BLArch Bachelor of Landscape Architecture Practice Test