CHT Irrigation & Water Management 2 — Questions and Answers
Question 1: A rain sensor or rain shutoff device is used in irrigation systems to:
- Boost water pressure after rain
- Automatically suspend irrigation during and after rainfall (Correct answer)
- Detect irrigation leaks
- Measure soil moisture
Correct answer: Automatically suspend irrigation during and after rainfall
Rain sensors detect rainfall and temporarily shut off the irrigation controller, preventing wasteful watering during and after rain events.
Question 2: What is 'water hammer' in irrigation systems?
- A tool used to drive stakes
- A pressure surge caused by rapid valve closure (Correct answer)
- Mineral buildup in pipes
- Excessive water pressure at emitters
Correct answer: A pressure surge caused by rapid valve closure
Water hammer is a pressure shock wave created when valves close rapidly, potentially damaging pipes, fittings, and heads in the irrigation system.
Question 3: In the US, which organization publishes water-efficient landscape standards relevant to CHT professionals?
- EPA WaterSense (Correct answer)
- USDA NRCS
- OSHA
- ANSI/ASME
Correct answer: EPA WaterSense
EPA WaterSense sets performance standards and certifies water-efficient irrigation products and practices widely referenced by horticulture professionals.
Question 4: Which irrigation scheduling method uses soil moisture sensors?
- Calendar-based scheduling
- ET-based scheduling
- Soil moisture-based scheduling (Correct answer)
- Visual inspection scheduling
Correct answer: Soil moisture-based scheduling
Soil moisture-based scheduling uses sensors (tensiometers, capacitance probes) to trigger irrigation only when soil moisture falls below a set threshold.
Question 5: Drip emitters are typically rated by their flow rate in:
- Gallons per minute (GPM)
- Gallons per hour (GPH) (Correct answer)
- Cubic feet per second (CFS)
- Liters per second (LPS)
Correct answer: Gallons per hour (GPH)
Drip emitters deliver water very slowly and are rated in gallons per hour (GPH), with common rates of 0.5, 1, and 2 GPH.
Question 6: What causes 'dry spots' in an otherwise irrigated lawn?
- Over-watering adjacent zones
- Poor head-to-head coverage or clogged nozzles (Correct answer)
- Excess fertilizer application
- Too much shade
Correct answer: Poor head-to-head coverage or clogged nozzles
Dry spots in irrigated turf typically result from inadequate head-to-head coverage, clogged nozzles, or misaligned heads creating gaps in the spray pattern.
CHT Irrigation & Water Management 2
A rain sensor or rain shutoff device is used in irrigation systems to: