Outsloping

What – Altering road template.  Outsloping is accomplished with an excavator, dozer, and grader (the excavator pulls back fill and places the material in the ditch; the dozer assists in moving and reshaping the road profile; and the grader completes the final profile).

Purpose – Disperse water along fill slope and reduce erosion; prevent concentration of flow on road surface that would otherwise cause rill, gully, and rut erosion.

Effectiveness – No effectiveness monitoring data is available.  Informal observations indicate immediate and long-term facility and resource benefits, including less sediment delivered to stream channels and reduced road maintenance.  In areas with highly erodible soils, outsloping roads with unvegetated soils may increase erosion.  Outsloping is often combined with other road treatments, including rolling dips and armored crossings to control water.

Where

• Within areas of high- and moderate-burn severity where loss of control of water is a risk particularly on flat road grades (< 10%).

Cost – $2 per linear foot.  Additional factors include:

• Road prism shape (inslope or outslope)
• Size and extent of existing berm
• Presence and extent of vegetation

How to Link – See USDA BAER Catalog page 106 (PDF page 144).