Gabion inflow protection must be used on slopes steeper than what ratio?

Gabion inflow protection is an important practice in erosion and sediment control, particularly on steeper slopes where the risk of erosion increases. The use of gabions, which are wire mesh containers filled with rock, helps to stabilize soil and manage the flow of water, preventing erosion and sediment loss.

For slopes steeper than a 4:1 ratio, the risk of surface runoff and erosion becomes significantly more pronounced. This indicates that for any vertical rise, there must be at least four horizontal units to reduce the intensity of water flow and allow for adequate sediment control. Going beyond this steepness increases the challenges of maintaining soil stability and managing runoff effectively. In this context, utilizing gabion inflow protection becomes critical to mitigate erosion and maintain the integrity of the slope.

Therefore, the correct answer reflects the recommended practice for using gabion inflow protection on slopes that exceed this 4:1 threshold, ensuring that erosion control measures are appropriately applied to prevent environmental degradation.