CSLB C-27 Landscaping ContractorSite Preparation and DrainageMedium
A landscape contractor is planning a new planting area on a recently graded site. The grading operation involved significant cut and fill. The site has a moderate slope (10%), and the contractor is concerned about potential erosion during establishment. Which of the following erosion control methods would provide the most immediate and effective protection for the newly graded slope while vegetation is establishing?
- AConstructing small, temporary straw wattles across the slope contour.
- BApplying a thick layer of organic mulch (e.g., wood chips).
- CHydroseeding with a fast-germinating grass mix.
- DInstalling erosion control blankets (ECBs) or turf reinforcement mats (TRMs).
Show answer & explanationAnswer & explanation
Correct answer: D. Installing erosion control blankets (ECBs) or turf reinforcement mats (TRMs).
Erosion control blankets (ECBs) or turf reinforcement mats (TRMs) provide immediate physical protection to the soil surface, stabilizing it against rain and wind erosion while allowing vegetation to establish through the mat. They are highly effective on moderate slopes.
Why the other options are wrong
- A. Straw wattles are effective at slowing runoff and trapping sediment, but they don't provide comprehensive surface protection against sheet erosion across the entire slope face.
- B. Organic mulch can help, but on a 10% slope, it may be displaced by heavy rain and not offer as robust immediate protection as a blanket system.
- C. Hydroseeding provides vegetative cover, but it takes time for germination and root establishment, leaving the soil vulnerable in the interim.
Immediate Slope Erosion Control
Methods used to quickly protect newly graded slopes from erosion before vegetation can fully establish.
- ECBs/TRMs provide immediate physical protection.
- They stabilize soil and reduce runoff velocity.
- Vegetation grows through the mats for long-term stability.
Memory trick: BLANKETS offer the best immediate SHIELD for slopes.