Landscape Design Grading and Drainage 2

Question 1

What is a French drain?

Accepted Answer

A gravel-filled trench containing a perforated pipe that redirects groundwater away from an area

Answer

A French drain is a subsurface drainage solution consisting of a gravel-filled trench with a perforated pipe that collects and redirects groundwater away from problem areas.

Question 2

What is the primary purpose of a retaining wall in landscape grading?

Accepted Answer

To hold back soil and resist lateral earth pressure on graded or terraced slopes

Answer

Retaining walls are structural elements engineered to hold back soil and resist lateral earth pressure when significant changes in grade must be maintained.

Question 3

What term describes water that flows across the soil surface rather than infiltrating into the ground?

Accepted Answer

Runoff

Answer

Runoff is water that flows over the ground surface when precipitation exceeds the soil's infiltration capacity or when the surface is impervious.

Question 4

What does 'daylighting' a drain mean in landscape design?

Accepted Answer

Extending a drainage pipe until it opens to the surface at a lower elevation

Answer

Daylighting refers to extending an underground drainage pipe to the surface at a lower point so water can exit the system by gravity into a vegetated area or waterway.

Question 5

What is the primary function of a dry well in a landscape drainage system?

Accepted Answer

To provide a subsurface reservoir that allows collected water to slowly percolate into surrounding soil

Answer

A dry well is an underground structure designed to temporarily hold stormwater and allow it to gradually infiltrate into the surrounding native soil.

Landscape Design Practice Test

Landscape Design Practice Test

Landscape Design Grading and Drainage 2