CGM CGM Irrigation & Water Management 2 — Questions and Answers
Question 1: What is 'distribution uniformity' (DU) in irrigation, and why does it matter?
- The schedule frequency for each zone; it matters for record-keeping
- A measure of how evenly water is applied across an irrigated area; low DU means some areas are over- or under-watered (Correct answer)
- The pipe size selected for each zone; it affects flow rate
- The distance between valve boxes; it affects maintenance access
Correct answer: A measure of how evenly water is applied across an irrigated area; low DU means some areas are over- or under-watered
DU quantifies consistency of water application across a zone; poor uniformity leads to drought stress in dry spots or disease and waste in wet spots.
Question 2: When conducting a catch-can test on a turf irrigation system, what is being measured?
- Soil pH across the irrigated zone
- The uniformity and precipitation rate of sprinkler coverage (Correct answer)
- Evapotranspiration rates over a 24-hour period
- Root depth of the turfgrass
Correct answer: The uniformity and precipitation rate of sprinkler coverage
A catch-can test places containers throughout a zone to collect applied water, revealing distribution uniformity and the actual precipitation rate delivered.
Question 3: Which irrigation scheduling strategy is considered most water-efficient for established turfgrass?
- Daily light watering to keep the surface moist
- Deep, infrequent watering that wets the full root zone and allows soil to partially dry between cycles (Correct answer)
- Watering at midday when evaporation is highest
- Irrigating based on a fixed calendar schedule regardless of weather
Correct answer: Deep, infrequent watering that wets the full root zone and allows soil to partially dry between cycles
Deep, infrequent irrigation promotes deeper root growth and allows the soil to partially dry, reducing fungal disease pressure and total water use.
Question 4: What is the function of a master valve in an irrigation system?
- To control water pressure at the meter
- To serve as a main shutoff that closes when the system is not actively running, preventing leaks from faulty zone valves (Correct answer)
- To filter sediment before the backflow preventer
- To boost water pressure for rotary sprinklers
Correct answer: To serve as a main shutoff that closes when the system is not actively running, preventing leaks from faulty zone valves
A master valve acts as a failsafe shutoff installed at the system's water source that only opens when a zone valve is scheduled to run.
Question 5: In the US, which entity typically regulates irrigation water use restrictions during drought conditions?
- The federal EPA exclusively
- State and local water authorities or municipalities (Correct answer)
- The National Weather Service
- The US Army Corps of Engineers
Correct answer: State and local water authorities or municipalities
Water use restrictions during drought are primarily managed by state water agencies and local water utilities, which issue mandatory or voluntary conservation orders.
Question 6: What is 'cycle and soak' programming in irrigation controllers designed to address?
- Frost protection for cold-sensitive plants
- Runoff from compacted or sloped soils by applying water in shorter, repeated cycles with rest intervals (Correct answer)
- Pressure fluctuations in aging pipe systems
- Scheduling conflicts between overlapping zones
Correct answer: Runoff from compacted or sloped soils by applying water in shorter, repeated cycles with rest intervals
Cycle and soak breaks a watering cycle into multiple short runs with rest periods, allowing water to infiltrate before more is applied, reducing runoff.
CGM CGM Irrigation & Water Management 2
What is 'distribution uniformity' (DU) in irrigation, and why does it matter?