CSM Sustainable Practices & Conservation 2 — Questions and Answers
Question 1: Which green infrastructure practice uses vegetation and soil to remove pollutants while allowing stormwater to infiltrate into the ground?
- Detention pond
- Bioretention cell (Correct answer)
- Concrete channel
- Riprap lining
Correct answer: Bioretention cell
Bioretention cells (rain gardens) use engineered soil media and plants to filter and infiltrate stormwater runoff.
Question 2: What is the primary purpose of a constructed wetland in a stormwater management system?
- Increase runoff velocity
- Provide water quality treatment through biological processes (Correct answer)
- Replace detention storage
- Prevent groundwater recharge
Correct answer: Provide water quality treatment through biological processes
Constructed wetlands use aquatic vegetation and microbial activity to remove nutrients, sediments, and other pollutants from stormwater.
Question 3: A municipality installs permeable pavers in a parking lot. What is the MOST direct hydrologic benefit?
- Increased peak discharge
- Reduced surface runoff volume (Correct answer)
- Higher evaporation rates
- Faster runoff concentration time
Correct answer: Reduced surface runoff volume
Permeable pavers allow water to infiltrate through joints or pores, directly reducing the volume of surface runoff generated.
Question 4: Which metric best evaluates whether a Low Impact Development (LID) design meets volume-based runoff performance standards?
- Peak discharge reduction percentage
- Runoff volume retention or capture depth (Correct answer)
- Time of concentration
- Curve number difference
Correct answer: Runoff volume retention or capture depth
Volume-based LID standards are typically evaluated by how much runoff depth (e.g., first 1 inch) is retained or captured on-site.
Question 5: Tree canopy interception contributes to stormwater management primarily by:
- Increasing impervious surface area
- Temporarily storing rainfall on leaves and branches before evaporation (Correct answer)
- Accelerating runoff to streams
- Reducing soil infiltration capacity
Correct answer: Temporarily storing rainfall on leaves and branches before evaporation
Tree canopies intercept rainfall, holding it on leaf surfaces where it evaporates rather than reaching the ground as runoff.
Question 6: A rain barrel system is best described as what type of conservation practice?
- End-of-pipe treatment
- Source control harvesting (Correct answer)
- Regional detention
- Channel modification
Correct answer: Source control harvesting
Rain barrels capture rooftop runoff at the source for later reuse, classifying them as source control and water harvesting practices.
Question 7: Which sustainable landscape practice most directly reduces the nutrient load in stormwater runoff from residential turf areas?
- Applying slow-release fertilizers only during dry weather
- Replacing turf with native plantings requiring no fertilization (Correct answer)
- Installing lawn sprinklers for consistent irrigation
- Aerating soil annually to increase compaction
Correct answer: Replacing turf with native plantings requiring no fertilization
Replacing fertilizer-dependent turf with native plants eliminates the nutrient source rather than managing it, most directly reducing nutrient runoff.
CSM Sustainable Practices & Conservation 2
Which green infrastructure practice uses vegetation and soil to remove pollutants while allowing stormwater to infiltrate into the ground?