Landscape Design Irrigation and Water Management 2 — Questions and Answers
Question 1: What is water hammer in an irrigation system and how is it prevented?
- Pressure surge from rapid valve closure, prevented by slow-closing valves (Correct answer)
- Water pressure drop from clogged emitters
- Backflow caused by broken pipe
- Air trapped in lines causing gurgling
Correct answer: Pressure surge from rapid valve closure, prevented by slow-closing valves
Water hammer is a damaging pressure spike caused by rapid valve closure; it is prevented by using slow-closing solenoid valves or pressure regulators.
Question 2: Which EPA program helps consumers identify water-efficient irrigation products and practices?
- WaterSense (Correct answer)
- EnergyStar
- Green Building Initiative
- LEED
Correct answer: WaterSense
EPA's WaterSense program labels water-efficient irrigation controllers, sprinkler heads, and other products that meet efficiency standards.
Question 3: What does an ET-based or smart irrigation controller use to adjust watering schedules?
- Evapotranspiration data from weather sensors (Correct answer)
- Soil moisture readings only
- Rainfall totals from a rain gauge
- Time-of-day scheduling only
Correct answer: Evapotranspiration data from weather sensors
ET-based controllers use local evapotranspiration data combining temperature, humidity, wind, and solar radiation to automatically adjust irrigation run times.
Question 4: What is head-to-head coverage in sprinkler system design?
- Each sprinkler's throw radius reaches the adjacent sprinkler head (Correct answer)
- Sprinkler heads aimed directly at each other
- Two sprinkler systems on the same zone
- Overlapping spray from opposite heads
Correct answer: Each sprinkler's throw radius reaches the adjacent sprinkler head
Head-to-head coverage means each sprinkler is spaced so its water throw reaches the next head, ensuring 100 percent coverage and uniform water distribution.
Question 5: Which soil type requires shorter, more frequent irrigation cycles due to its low infiltration rate?
- Clay soil (Correct answer)
- Sandy soil
- Loam soil
- Gravelly soil
Correct answer: Clay soil
Clay soil has a very low infiltration rate and is prone to runoff, requiring short, cycled irrigation to allow water to penetrate slowly.
Question 6: What is the recommended maximum soil moisture deficit before irrigating established turfgrass?
- 50 percent of plant available water depleted (Correct answer)
- 10 percent depleted
- 100 percent depleted
- 25 percent depleted
Correct answer: 50 percent of plant available water depleted
Irrigating when approximately 50 percent of plant available water is depleted balances turf health with water conservation and avoids stress or waste.
Landscape Design Irrigation and Water Management 2
What is water hammer in an irrigation system and how is it prevented?