CFB CFB Drainage & Irrigation Systems 1 — Questions and Answers
Question 1: What is the recommended minimum slope for surface drainage on a natural grass athletic field?
- 0.5%
- 1.0% (Correct answer)
- 1.5%
- 2.0%
Correct answer: 1.0%
A minimum 1.0% slope is recommended for natural grass athletic fields to ensure effective surface water runoff.
Question 2: Which type of subsurface drainage system uses perforated pipes installed in gravel-filled trenches beneath a field?
- French drain system (Correct answer)
- Curtain drain system
- Interceptor drain system
- Slit drain system
Correct answer: French drain system
A French drain system uses perforated pipes surrounded by gravel-filled trenches to collect and redirect subsurface water.
Question 3: What is the primary purpose of a rootzone drainage layer in a sand-based athletic field?
- To provide nutrients to grass roots
- To allow rapid percolation of water away from the playing surface (Correct answer)
- To stabilize the soil against compaction
- To insulate against frost damage
Correct answer: To allow rapid percolation of water away from the playing surface
The rootzone drainage layer in sand-based fields is designed to allow water to percolate quickly downward, keeping the surface playable.
Question 4: In athletic field irrigation design, what does 'distribution uniformity' (DU) measure?
- The total volume of water applied per irrigation cycle
- The consistency of water application across the irrigated area (Correct answer)
- The pressure at the irrigation pump outlet
- The flow rate of individual sprinkler heads
Correct answer: The consistency of water application across the irrigated area
Distribution uniformity measures how evenly water is applied across an irrigation zone, with higher DU values indicating more consistent coverage.
Question 5: Which factor most directly determines the spacing between lateral drainage pipes in an athletic field?
- The field's intended sport use
- The hydraulic conductivity of the soil (Correct answer)
- The annual precipitation of the region
- The depth of the water table
Correct answer: The hydraulic conductivity of the soil
Soil hydraulic conductivity determines how quickly water moves laterally through the soil, which directly governs the required spacing between drainage pipes.
Question 6: What is the standard installation depth for main collector drain lines beneath athletic fields in the US?
- 6–12 inches
- 18–24 inches
- 36–48 inches (Correct answer)
- 60–72 inches
Correct answer: 36–48 inches
Main collector drain lines are typically installed at 36–48 inches depth to stay below the rootzone and avoid interference with field maintenance equipment.
CFB CFB Drainage & Irrigation Systems 1
What is the recommended minimum slope for surface drainage on a natural grass athletic field?