CPH CPH Irrigation and Water Management 1 — Questions and Answers
Question 1: What is the primary purpose of a backflow preventer on a landscape irrigation system?
- To boost water pressure at the irrigation mainline
- To prevent contaminated irrigation water from flowing back into the potable water supply (Correct answer)
- To regulate and maintain consistent flow rate throughout the system
- To filter sediment and debris from the water supply
Correct answer: To prevent contaminated irrigation water from flowing back into the potable water supply
A backflow preventer stops potentially contaminated irrigation water from flowing backward into the potable water supply, protecting public health.
Question 2: In irrigation, 'precipitation rate' is defined as:
- The average annual rainfall for a given region
- The rate at which water is applied to a given area, typically measured in inches per hour (Correct answer)
- The percentage of water that reaches plant roots versus evaporation losses
- The operating pressure of sprinkler heads at the nozzle
Correct answer: The rate at which water is applied to a given area, typically measured in inches per hour
Precipitation rate is the amount of water applied to an area per unit of time (inches per hour), and matching rates across a zone ensures uniform coverage.
Question 3: Which irrigation method is generally considered the most water-efficient for landscape and garden use?
- Overhead rotary sprinklers
- Flood or furrow irrigation
- Drip or micro-irrigation (Correct answer)
- Hand watering with a spray wand
Correct answer: Drip or micro-irrigation
Drip and micro-irrigation deliver water directly to the root zone with minimal evaporation and surface runoff, making them the most efficient delivery method.
Question 4: In irrigation system evaluation, 'distribution uniformity' measures:
- The spacing distance between individual sprinkler heads
- How evenly water is applied across the entire irrigated area (Correct answer)
- The total number of irrigation zones in the system
- Water pressure variation from the meter to the farthest head
Correct answer: How evenly water is applied across the entire irrigated area
Distribution uniformity quantifies how evenly water is distributed across an irrigated area; higher values indicate more uniform application.
Question 5: In irrigation scheduling, 'ET' (evapotranspiration) refers to:
- The total annual precipitation recorded at a weather station
- The combined water loss from soil evaporation and plant transpiration (Correct answer)
- The efficiency rating assigned to irrigation equipment
- The electrical conductivity measurement of irrigation water
Correct answer: The combined water loss from soil evaporation and plant transpiration
Evapotranspiration (ET) is the sum of water lost through soil evaporation and plant transpiration, and is used to calculate how much water to replace through irrigation.
Question 6: The 'head-to-head' coverage principle in sprinkler system design specifies that:
- Sprinkler heads must face directly opposite each other in all zones
- Each sprinkler's throw radius must reach the adjacent sprinkler head (Correct answer)
- Only one brand of sprinkler head should be used per system
- Sprinkler heads must be raised on pedestals to achieve coverage
Correct answer: Each sprinkler's throw radius must reach the adjacent sprinkler head
Head-to-head coverage means each sprinkler's radius reaches the neighboring head, providing 100% overlap and compensating for wind effects and pressure losses.
CPH CPH Irrigation and Water Management 1
What is the primary purpose of a backflow preventer on a landscape irrigation system?