PDC Sustainable Land Use & Water Management 4 — Questions and Answers
Question 1: Which of the following best describes a 'constructed wetland' in permaculture water management?
- A decorative pond built purely for aesthetic purposes
- An engineered shallow-water system that uses plants and microbes to treat greywater or stormwater (Correct answer)
- A naturally occurring wetland protected from human disturbance
- A flooded field used for rice cultivation only
Correct answer: An engineered shallow-water system that uses plants and microbes to treat greywater or stormwater
Constructed wetlands are engineered systems using aquatic plants and microbial communities to biologically treat wastewater or stormwater before reuse or discharge.
Question 2: In a permaculture design, 'grey water' is best managed using which approach?
- Directing it to municipal sewage treatment facilities only
- Irrigating fruit trees and gardens after basic filtration through a mulch basin (Correct answer)
- Storing it in sealed tanks for eventual disposal
- Releasing it directly into natural waterways to dilute contaminants
Correct answer: Irrigating fruit trees and gardens after basic filtration through a mulch basin
Greywater from sinks and showers can safely irrigate non-edible plant surfaces or fruit trees after passing through mulch basins that filter pathogens.
Question 3: Which earthwork technique is specifically designed to move water from wetter valleys toward drier ridges on a property?
- French drain installation
- Keyline plowing along off-contour lines (Correct answer)
- Contour swales running exactly on-contour
- Berms placed perpendicular to slope
Correct answer: Keyline plowing along off-contour lines
Keyline plowing runs slightly off-contour, angled to move water laterally from valley floors toward ridgelines over repeated irrigation cycles.
Question 4: What is the primary ecological function of 'nurse plants' in dryland permaculture land restoration?
- They produce medicinal herbs for human use
- They provide shade, wind protection, and improved microclimate for establishing more sensitive species (Correct answer)
- They are planted solely to fix nitrogen in the soil
- They serve as windbreaks to protect cash crops from wind damage
Correct answer: They provide shade, wind protection, and improved microclimate for establishing more sensitive species
Nurse plants create a protective microclimate—reduced temperature extremes, wind, and evaporation—that enables more sensitive plants to establish in harsh dryland conditions.
Question 5: On a 5-acre property receiving 30 inches of annual rainfall, approximately how many gallons of rainwater fall on the property each year?
- Approximately 250,000 gallons
- Approximately 500,000 gallons
- Approximately 4,075,000 gallons (Correct answer)
- Approximately 12,000,000 gallons
Correct answer: Approximately 4,075,000 gallons
5 acres × 43,560 sq ft/acre × 2.5 ft (30 inches) × 7.48 gal/cu ft ≈ 4,075,000 gallons annually.
Question 6: Which principle explains why permaculture designs often integrate ponds higher in the landscape rather than only at the lowest point?
- High ponds are easier to excavate than low-lying ponds
- High ponds allow gravity-fed irrigation distribution throughout the property (Correct answer)
- Water at elevation is cleaner than water collected at the base
- High ponds reduce evaporation losses compared to low ponds
Correct answer: High ponds allow gravity-fed irrigation distribution throughout the property
Elevated ponds use gravity to distribute water by pipeline or channel throughout the property, eliminating pump energy costs.
Question 7: Which land use pattern is most consistent with permaculture's approach to marginal, steep, or fragile land?
- Intensive annual cropping to maximize productivity per acre
- Leaving it entirely wild with no human management
- Permanent perennial cover, agroforestry, or minimal-disturbance grazing (Correct answer)
- Terracing for intensive vegetable production
Correct answer: Permanent perennial cover, agroforestry, or minimal-disturbance grazing
Marginal and fragile lands require low-disturbance management—perennial plants, agroforestry, or light grazing—to prevent erosion and ecosystem degradation.
PDC Sustainable Land Use & Water Management 4
Which of the following best describes a 'constructed wetland' in permaculture water management?