Which method is NOT typically included in outlet protection measures?

Outlet protection measures are designed to prevent erosion and sedimentation at the outlet of stormwater management systems, such as pipes or channels. The correct method that is NOT typically included in these measures is vegetative cover.

Vegetative cover is primarily used for erosion control on bare soil or land surfaces rather than at outlets, where the focus is on dissipating energy and controlling flow to prevent scouring. While vegetation can help stabilize soils and mitigate erosion over time, it does not directly address the immediate concerns associated with concentrated flow at an outlet, where heavier structural measures are more effective.

In contrast, riprap, gabion baskets, and grouted riprap are all structural methods designed specifically for protecting outlets. Riprap consists of large, loose stones used to create a permeable layer that absorbs energy from flowing water. Gabion baskets are wire mesh cages filled with rocks that provide stability and erosion resistance. Grouted riprap combines the use of stone with cement to create a more stable, solid structure at the outlet, further reducing the risk of erosion.

Each of these structural methods is tailored to handle the dynamic forces present at outlets, making them essential components of outlet protection systems, unlike vegetative cover, which is not designed for such direct applications.