Crossing at Kill Creek

Armoring is a method of using large rocks to harden or pave a section of trail to help prevent erosion. Armoring is frequently used on sections of trail that cross areas that are frequently soft and/or wet.

While routing the trail around these areas is always the best solution, sometimes it is just not possible. A properly built contour trail will follow along hillsides and their natural drainage points. It is nearly inevitable that you will encounter water when routing your trail.

 

 

 

Care must be taken to prevent erosion, or even damage to the surrounding environment.

IMBA's Trail Solutions guide to building singletrack describes 6 ways that armoring can benefit a trail:

• Hardening a contour trail in extremely rainy climates
• Stabilizing steep sections of contour trail with grades from 20 to 45 percent
• Reinforcing stream crossings
• Crossing low-lying or muddy or sandy area where reroute isn't possible
• Hardening landing areas following jumps or drop-offs.
• Toughening the trail surface on high-traffic routes to withstand user-caused erosion.

The first step in the armoring process is to select an area that is often wet, or is suffering from user-caused erosion. In our example, we have selected a low-lying area and marked it in advance with pink pin-flags.

 

 

The next step is to locate and collect some very large rocks. Large, flat-faced stones are widely available in our area, so the "flagstone paving" technique of armoring is very popular. Each stone is laid with it's flattest surface facing up, at the same grade as the tread surface.

 

 

 

 

 

 

The final step is to fill in the gaps with good mineral soil or gravel. This will help reduce the amount of settling that occurs